92 results on '"A. Deutschmann"'
Search Results
2. Optimal Sensing of Momentum Kicks with a Feedback-Controlled Nanomechanical Resonator
- Author
-
Schmerling, Kaspar, Bešić, Hajrudin, Kugi, Andreas, Schmid, Silvan, and Deutschmann-Olek, Andreas
- Subjects
Electrical Engineering and Systems Science - Systems and Control ,Physics - Applied Physics - Abstract
External disturbances exciting a mechanical resonator can be exploited to gain information on the environment. Many of these interactions manifest as momentum kicks, such as the recoil of residual gas, radioactive decay, or even hypothetical interactions with dark matter. These disturbances are often rare enough that they can be resolved as singular events rather than cumulated as force noise. While high-Q resonators with low masses are particularly sensitive to such momentum kicks, they will strongly excite the resonator, leading to nonlinear effects that deteriorate the sensing performance. Hence, this paper utilizes optimal estimation methods to extract individual momentum kicks from measured stochastic trajectories of a mechanical resonator kept in the linear regime through feedback control. The developed scheme is illustrated and tested experimentally using a pre-stressed SiN trampoline resonator. Apart from enhancing a wide range of sensing scenarios mentioned above, our results indicate the feasibility of novel single-molecule mass spectrometry approaches., Comment: 8 pages, 7 figures more...
- Published
- 2024
Catalog
3. Single versus Multi-Tone Wireless Power Transfer with Physically Large Array
- Author
-
Van Mulders, Jarne, Deutschmann, Benjamin J. B., Ottoy, Geoffrey, De Strycker, Lieven, Van der Perre, Liesbet, Wilding, Thomas, and Callebaut, Gilles
- Subjects
Electrical Engineering and Systems Science - Systems and Control - Abstract
Distributed beamforming is a key enabler to provide power wirelessly to a massive amount of energy-neutral devices (ENDs). However, without prior information and fully depleted ENDs, initially powering these devices efficiently is an open question. This work investigates and assesses the feasibility of harvesting sufficient energy to transmit a backscatter pilot signal from the END, which can be then used for coherent downlink transmission. We experimentally evaluated adaptive single-tone and multi-tone signals during initial charging. The results indicate that the response time for ENDs with unknown locations can extend to several tens of seconds. Notably, the adaptive single-tone excitation shows, among others, better performance at lower transmit power levels, providing a faster response. These findings underscore the potential of adaptive single-tone signals in optimizing power delivery to END in future networks., Comment: 1st International Workshop on Energy Neutral and Sustainable IoT Devices and Infrastructure (EN-IoT 2024) more...
- Published
- 2024
4. Joint Localization, Synchronization and Mapping via Phase-Coherent Distributed Arrays
- Author
-
Fascista, Alessio, Deutschmann, Benjamin J. B., Keskin, Musa Furkan, Wilding, Thomas, Coluccia, Angelo, Witrisal, Klaus, Leitinger, Erik, Seco-Granados, Gonzalo, and Wymeersch, Henk
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Extremely large-scale antenna array (ELAA) systems emerge as a promising technology in beyond 5G and 6G wireless networks to support the deployment of distributed architectures. This paper explores the use of ELAAs to enable joint localization, synchronization and mapping in sub-6 GHz uplink channels, capitalizing on the near-field effects of phase-coherent distributed arrays. We focus on a scenario where a single-antenna user equipment (UE) communicates with a network of access points (APs) distributed in an indoor environment, considering both specular reflections from walls and scattering from objects. The UE is assumed to be unsynchronized to the network, while the APs can be time- and phase-synchronized to each other. We formulate the problem of joint estimation of location, clock offset and phase offset of the UE, and the locations of scattering points (SPs) (i.e., mapping). Through comprehensive Fisher information analysis, we assess the impact of bandwidth, AP array size, wall reflections, SPs and phase synchronization on localization accuracy. Furthermore, we derive the maximum-likelihood (ML) estimator, which optimally combines the information collected by all the distributed arrays. To overcome its intractable high dimensionality, we propose a novel three-step algorithm that first estimates phase offset leveraging carrier phase information of line-of-sight (LoS) paths, then determines the UE location and clock offset via LoS paths and wall reflections, and finally locates SPs using a null-space transformation technique. Simulation results demonstrate the effectiveness of our approach in distributed architectures supported by radio stripes (RSs) -- an innovative alternative for implementing ELAAs -- while revealing the benefits of carrier phase exploitation and showcasing the interplay between delay and angular information under different bandwidth regimes. more...
- Published
- 2024
5. Steady-state entanglement of interacting masses in free space through optimal feedback control
- Author
-
Winkler, Klemens, Zasedatelev, Anton V., Stickler, Benjamin A., Delić, Uroš, Deutschmann-Olek, Andreas, and Aspelmeyer, Markus
- Subjects
Quantum Physics - Abstract
We develop a feedback strategy based on optimal quantum feedback control for Gaussian systems to maximise the likelihood of steady-state entanglement detection between two directly interacting masses. We employ linear quadratic Gaussian (LQG) control to engineer the phase space dynamics of the two masses and propose Einstein-Podolsky-Rosen (EPR)-type variance minimisation constraints for the feedback to facilitate unconditional entanglement generation. This scheme allows for stationary entanglement in parameter regimes where strategies based on total energy minimisation ($cooling$) would fail. This feedback strategy, applied to the system of two masses driven out-of-thermal equilibrium [arXiv:2408.06251] enables unconditional entanglement generation under realistic experimental conditions. more...
- Published
- 2024
6. VeriCHERI: Exhaustive Formal Security Verification of CHERI at the RTL
- Author
-
Antón, Anna Lena Duque, Müller, Johannes, Schmitz, Philipp, Jauch, Tobias, Wezel, Alex, Deutschmann, Lucas, Fadiheh, Mohammad Rahmani, Stoffel, Dominik, and Kunz, Wolfgang
- Subjects
Computer Science - Cryptography and Security - Abstract
Protecting data in memory from attackers continues to be a concern in computing systems. CHERI is a promising approach to achieve such protection, by providing and enforcing fine-grained memory protection directly in the hardware. Creating trust for the entire system stack, however, requires a gap-free verification of CHERI's hardware-based protection mechanisms. Existing verification methods for CHERI target the abstract ISA model rather than the underlying hardware implementation. Fully ensuring the CHERI security guarantees for a concrete RTL implementation is a challenge in previous flows and demands high manual efforts. This paper presents VeriCHERI, a novel approach to security verification. It is conceptionally different from previous works in that it does not require any ISA specification. Instead of checking compliance with a golden ISA model, we check against well-established global security objectives of confidentiality and integrity. Fully covering these objectives, VeriCHERI uses as few as four unbounded properties to exhaustively prove or disprove any vulnerability. We demonstrate the effectiveness and scalability of VeriCHERI on a RISC-V based processor implementing a CHERI variant., Comment: Accepted for publication at the 43rd International Conference on Computer-Aided Design (ICCAD `24), Oct 27-31, 2024, New Jersey, USA more...
- Published
- 2024
- Full Text
- View/download PDF
7. Optimized Signal Estimation in Nanomechanical Photothermal Sensing via Thermal Response Modelling and Kalman Filtering
- Author
-
Bešić, Hajrudin, Deutschmann-Olek, Andreas, Mešić, Kenan, Kanellopulos, Kostas, and Schmid, Silvan
- Subjects
Physics - Applied Physics - Abstract
We present an advanced thermal response model for micro- and nanomechanical systems in photothermal sensing, designed to balance speed and precision. Our model considers the two time constants of the nanomechanical element and the supporting chip, triggered by photothermal heating, enabling precise photothermal input signal estimation through Kalman filtering. By integrating heat transfer and noise models, we apply an adaptive Kalman filter optimized for FPGA systems in real-time or offline. This method, used for photothermal infrared (IR) spectroscopy with nanomechanical resonators and a quantum cascade laser (QCL) in step-scan mode, enhances response speed beyond standard low-pass filters, reducing the effects of drift and random walk. Analytical calculations show the significant impact of the thermal expansion coefficients' ratio on the frequency response. The adaptive Kalman filter, informed by the QCL's input characteristics, accelerates the system's response, allowing rapid and precise IR spectrum generation. The use of the Levenberg-Marquardt algorithm and PSD analysis for system identification further refines our approach, promising fast and accurate nanomechanical photothermal sensing. more...
- Published
- 2024
8. Accurate Direct Positioning in Distributed MIMO Using Delay-Doppler Channel Measurements
- Author
-
Deutschmann, Benjamin J. B., Nelson, Christian, Henriksson, Mikael, Marti, Gian, Kosasih, Alva, Tervo, Nuutti, Leitinger, Erik, and Tufvesson, Fredrik
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Distributed multiple-input multiple-output (D-MIMO) is a promising technology for simultaneous communication and positioning. However, phase synchronization between multiple access points in D-MIMO is challenging and methods that function without the need for phase synchronization are highly desired. Therefore, we present a method for D-MIMO that performs direct positioning of a moving device based on the delay-Doppler characteristics of the channel state information (CSI). Our method relies on particle-filter-based Bayesian inference with a state-space model. We use recent measurements from a sub-6 GHz D-MIMO OFDM system in an industrial environment to demonstrate near-centimeter accuracy under partial line-of-sight (LoS) conditions and decimeter accuracy under fully obstructed LoS., Comment: 5 pages, 4 figures, accepted at IEEE SPAWC 2024 more...
- Published
- 2024
9. Distributed MIMO Measurements for Integrated Communication and Sensing in an Industrial Environment
- Author
-
Nelson, Christian, Li, Xuhong, Fedorov, Aleksei, Deutschmann, Benjamin J. B., and Tufvesson, Fredrik
- Subjects
Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Many concepts for future generations of wireless communication systems use coherent processing of signals from many distributed antennas. The aim is to improve communication reliability, capacity, and energy efficiency and provide possibilities for new applications through integrated communication and sensing. The large bandwidths available in the higher bands have inspired much work regarding sensing in the mmWave and sub-THz bands; however, the sub-6 GHz cellular bands will still be the main provider of wide cellular coverage due to the more favorable propagation conditions. In this paper, we present a measurement system and results of sub-6 GHz distributed MIMO measurements performed in an industrial environment. From the measurements, we evaluated the diversity for both large-scale and small-scale fading and characterized the link reliability. We also analyzed the possibility of multistatic sensing and positioning of users in the environment, with the initial results showing a mean-square error below 20 cm on the estimated position. Further, the results clearly showed that new channel models are needed that are spatially consistent and deal with the nonstationary channel properties among the antennas., Comment: 19 pages, 20 figure, Published in MDPI Sensors more...
- Published
- 2024
- Full Text
- View/download PDF
10. Keeping Energy-Neutral Devices Operational: a Coherent Massive Beamforming Approach
- Author
-
Van Mulders, Jarne, Cox, Bert, Deutschmann, Benjamin J. B., Callebaut, Gilles, de Strycker, Lieven, and Van der Perre, Liesbet
- Subjects
Electrical Engineering and Systems Science - Systems and Control - Abstract
Keeping the batteries on the shelf: this is the holy grail for low-cost Internet of Things (IoT) nodes. In this paper we study the potential of radio frequency (RF)-based wireless power transfer implementing coherent beamforming with many antennas to realize this ambitious target. We optimize the deployment of the antennas to charge electronic shelf labels (ESLs), considering actual regulatory constraints. The results confirm the feasibility to create power spots that are sufficient to keep the high density of battery-less devices operational. more...
- Published
- 2024
11. Accelerating HEP simulations with Neural Importance Sampling
- Author
-
Deutschmann, Nicolas and Götz, Niklas
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment ,High Energy Physics - Theory ,Physics - Computational Physics ,Physics - Data Analysis, Statistics and Probability - Abstract
Many high-energy-physics (HEP) simulations for the LHC rely on Monte Carlo using importance sampling by means of the VEGAS algorithm. However, complex high-precision calculations have become a challenge for the standard toolbox, as this approach suffers from poor performance in complex cases. As a result, there has been keen interest in HEP for modern machine learning to power adaptive sampling. While previous studies have shown the potential of normalizing-flow-powered neural importance sampling (NIS) over VEGAS, there remains a gap in accessible tools tailored for non-experts. In response, we introduce Z\"uNIS, a fully automated NIS library designed to bridge this divide, while at the same time providing the infrastructure to customise the algorithm for dealing with challenging tasks. After a general introduction on NIS, we first show how to extend the original formulation of NIS to reuse samples over multiple gradient steps while guaranteeing a stable training, yielding a significant improvement for slow functions. Next, we introduce the structure of the library, which can be used by non-experts with minimal effort and is extensivly documented, which is crucial to become a mature tool for the wider HEP public. We present systematic benchmark results on both toy and physics examples, and stress the benefit of providing different survey strategies, which allows higher performance in challenging cases. We show that Z\"uNIS shows high performance on a range of problems with limited fine-tuning., Comment: 31 pages, 11 figures more...
- Published
- 2024
12. A Golden-Free Formal Method for Trojan Detection in Non-Interfering Accelerators
- Author
-
Antón, Anna Lena Duque, Müller, Johannes, Deutschmann, Lucas, Fadiheh, Mohammad Rahmani, Stoffel, Dominik, and Kunz, Wolfgang
- Subjects
Computer Science - Cryptography and Security - Abstract
The threat of hardware Trojans (HTs) in security-critical IPs like cryptographic accelerators poses severe security risks. The HT detection methods available today mostly rely on golden models and detailed circuit specifications. Often they are specific to certain HT payload types, making pre-silicon verification difficult and leading to security gaps. We propose a novel formal verification method for HT detection in non-interfering accelerators at the Register Transfer Level (RTL), employing standard formal property checking. Our method guarantees the exhaustive detection of any sequential HT independently of its payload behavior, including physical side channels. It does not require a golden model or a functional specification of the design. The experimental results demonstrate efficient and effective detection of all sequential HTs in accelerators available on Trust-Hub, including those with complex triggers and payloads., Comment: Accepted for publication at the 27th Design, Automation and Test in Europe Conference (DATE'24), Mar 25-27 2024, Valencia, Spain more...
- Published
- 2023
13. An Open Dataset Storage Standard for 6G Testbeds
- Author
-
Callebaut, Gilles, Sandra, Michiel, Nelson, Christian, Wilding, Thomas, Delabie, Daan, Deutschmann, Benjamin J. B., Tärneberg, William, Fitzgerald, Emma, Johansson, Anders J., and Van der Perre, Liesbet more...
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
The emergence of sixth-generation (6G) networks has spurred the development of novel testbeds, including sub-THz networks, cell-free systems, and 6G simulators. To maximize the benefits of these systems, it is crucial to make the generated data publicly available and easily reusable by others. Although data sharing has become a common practice, a lack of standardization hinders data accessibility and interoperability. In this study, we propose the Dataset Storage Standard (DSS) to address these challenges by facilitating data exchange and enabling convenient processing script creation in a testbed-agnostic manner. DSS supports both experimental and simulated data, allowing researchers to employ the same processing scripts and tools across different datasets. Unlike existing standardization efforts such as SigMF and NI RF Data Recording API, DSS provides a broader scope by accommodating a common definition file for testbeds and is not limited to RF data storage. The dataset format utilizes a hierarchical structure, with a tensor representation for specific experiment scenarios. In summary, DSS offers a comprehensive and flexible framework for enhancing the FAIR principles (Findability, Accessibility, Interoperability, and Reusability) in 6G testbeds, promoting open and efficient data sharing in the research community. more...
- Published
- 2023
14. MCU-Wide Timing Side Channels and Their Detection
- Author
-
Müller, Johannes, Antón, Anna Lena Duque, Deutschmann, Lucas, Mehmedagić, Dino, Rodrigues, Cristiano, Oliveira, Daniel, Devarajegowda, Keerthikumara, Fadiheh, Mohammad Rahmani, Pinto, Sandro, Stoffel, Dominik, and Kunz, Wolfgang more...
- Subjects
Computer Science - Cryptography and Security - Abstract
Microarchitectural timing side channels have been thoroughly investigated as a security threat in hardware designs featuring shared buffers (e.g., caches) or parallelism between attacker and victim task execution. However, contradicting common intuitions, recent activities demonstrate that this threat is real even in microcontroller SoCs without such features. In this paper, we describe SoC-wide timing side channels previously neglected by security analysis and present a new formal method to close this gap. In a case study on the RISC-V Pulpissimo SoC, our method detected a vulnerability to a previously unknown attack variant that allows an attacker to obtain information about a victim's memory access behavior. After implementing a conservative fix, we were able to verify that the SoC is now secure w.r.t. the considered class of timing side channels., Comment: This version extends the work of the previous version and was accepted and presented at DAC'24 more...
- Published
- 2023
- Full Text
- View/download PDF
15. Conformal Autoregressive Generation: Beam Search with Coverage Guarantees
- Author
-
Deutschmann, Nicolas, Alberts, Marvin, and Martínez, María Rodríguez
- Subjects
Computer Science - Machine Learning - Abstract
We introduce two new extensions to the beam search algorithm based on conformal predictions (CP) to produce sets of sequences with theoretical coverage guarantees. The first method is very simple and proposes dynamically-sized subsets of beam search results but, unlike typical CP procedures, has an upper bound on the achievable guarantee depending on a post-hoc calibration measure. Our second algorithm introduces the conformal set prediction procedure as part of the decoding process, producing a variable beam width which adapts to the current uncertainty. While more complex, this procedure can achieve coverage guarantees selected a priori. We provide marginal coverage bounds for each method, and evaluate them empirically on a selection of tasks drawing from natural language processing and chemistry., Comment: 11 pages, 4 figures more...
- Published
- 2023
16. A Scalable Formal Verification Methodology for Data-Oblivious Hardware
- Author
-
Deutschmann, Lucas, Mueller, Johannes, Fadiheh, Mohammad Rahmani, Stoffel, Dominik, and Kunz, Wolfgang
- Subjects
Computer Science - Cryptography and Security - Abstract
The importance of preventing microarchitectural timing side channels in security-critical applications has surged in recent years. Constant-time programming has emerged as a best-practice technique for preventing the leakage of secret information through timing. It is based on the assumption that the timing of certain basic machine instructions is independent of their respective input data. However, whether or not an instruction satisfies this data-independent timing criterion varies between individual processor microarchitectures. In this paper, we propose a novel methodology to formally verify data-oblivious behavior in hardware using standard property checking techniques. The proposed methodology is based on an inductive property that enables scalability even to complex out-of-order cores. We show that proving this inductive property is sufficient to exhaustively verify data-obliviousness at the microarchitectural level. In addition, the paper discusses several techniques that can be used to make the verification process easier and faster. We demonstrate the feasibility of the proposed methodology through case studies on several open-source designs. One case study uncovered a data-dependent timing violation in the extensively verified and highly secure IBEX RISC-V core. In addition to several hardware accelerators and in-order processors, our experiments also include RISC-V BOOM, a complex out-of-order processor, highlighting the scalability of the approach. more...
- Published
- 2023
- Full Text
- View/download PDF
17. Adaptive Conformal Regression with Jackknife+ Rescaled Scores
- Author
-
Deutschmann, Nicolas, Rigotti, Mattia, and Martinez, Maria Rodriguez
- Subjects
Computer Science - Machine Learning ,Statistics - Machine Learning - Abstract
Conformal regression provides prediction intervals with global coverage guarantees, but often fails to capture local error distributions, leading to non-homogeneous coverage. We address this with a new adaptive method based on rescaling conformal scores with an estimate of local score distribution, inspired by the Jackknife+ method, which enables the use of calibration data in conformal scores without breaking calibration-test exchangeability. Our approach ensures formal global coverage guarantees and is supported by new theoretical results on local coverage, including an a posteriori bound on any calibration score. The strength of our approach lies in achieving local coverage without sacrificing calibration set size, improving the applicability of conformal prediction intervals in various settings. As a result, our method provides prediction intervals that outperform previous methods, particularly in the low-data regime, making it especially relevant for real-world applications such as healthcare and biomedical domains where uncertainty needs to be quantified accurately despite low sample data., Comment: 24 pages, 7 figures more...
- Published
- 2023
18. Propagation Modeling for Physically Large Arrays: Measurements and Multipath Component Visibility
- Author
-
Wilding, Thomas, Deutschmann, Benjamin J. B., Nelson, Christian, Li, Xuhong, Tufvesson, Fredrik, and Witrisal, Klaus
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
This paper deals with propagation and channel modeling for physically large arrays. The focus lies on acquiring a spatially consistent model, which is essential, especially for positioning and sensing applications. Ultra-wideband, synthetic array measurement data have been acquired with large positioning devices to support this research. We present a modified multipath channel model that accounts for a varying visibility of multipath components along a large array. Based on a geometric model of the measurement environment, we analyze the visibility of specular components. We show that, depending on the size of the reflecting surface, geometric visibility and amplitude estimates obtained with a super-resolution channel estimation algorithm show a strong correspondence. Furthermore, we highlight the capabilities of the developed synthetic array measurement system., Comment: 6 pages, 6 figures, submitted to EuCNC-2023 more...
- Published
- 2023
19. Bistatic MIMO Radar Sensing of Specularly Reflecting Surfaces for Wireless Power Transfer
- Author
-
Deutschmann, Benjamin J. B., Graber, Maximilian, Wilding, Thomas, and Witrisal, Klaus
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Geometric environment information aids future distributed radio infrastructures in providing services, such as ultra-reliable communication, positioning, and wireless power transfer (WPT). An a priori known environment model cannot always be assumed in practice. This paper investigates the capabilities of detecting specularly reflecting surfaces in a bistatic multiple-input multiple-output (MIMO) radar setup operating at sub-10 GHz frequencies. While rough surfaces generate diffuse reflections originating from their actual position, flat surfaces act like "mirrors," causing directive reflections that virtually originate "behind" them. Despite these propagation characteristics, we can estimate the locations of flat metal walls from reflections at their surface using synthetic aperture (SA) measurements. The performance gain achievable by exploiting this environment information is analyzed by evaluating WPT capabilities in a geometry-based beamforming setup. We show that it is possible to predict channel state information (CSI) with a geometric channel model. Our geometry-based beamformer suffers an efficiency loss of only 1.1dB compared with a reciprocity-based beamformer given perfect CSI. more...
- Published
- 2023
20. Large Intelligent Surface Measurements for Joint Communication and Sensing
- Author
-
Nelson, Christian, Li, Xuhong, Wilding, Thomas, Deutschmann, Benjamin, Witrisal, Klaus, and Tufvesson, Fredrik
- Subjects
Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Multiple concepts for future generations of wireless communication standards utilize coherent processing of signals from many distributed antennas. Names for these concepts include distributed MIMO, cell-free massive MIMO, XL-MIMO, and large intelligent surfaces. They aim to improve communication reliability, capacity, as well as energy efficiency and provide possibilities for new applications through joint communication and sensing. One such recently proposed solution is the concept of RadioWeaves. It proposes a new radio infrastructure for distributed MIMO with distributed internal processing, storage, and compute resources integrated into the infrastructure. The large bandwidths available in the higher bands have inspired much work regarding sensing in the mmWave- and sub-THz-bands, however, sub-6 GHz cellular bands will still be the main provider of broad cellular coverage due to the more favorable propagation conditions. In this paper, we present results from a sub-6 GHz measurement campaign targeting the non-stationary spatial channel statistics for a large RadioWeave and the temporal non-stationarity in a dynamic scenario with RadioWeaves. From the results, we also predict the possibility of multi-static sensing and positioning of users in the environment., Comment: 6 pages, 2 columns, 12 figures, IEEE European Conference on Networks and Communications & 6G Summit 2023 more...
- Published
- 2023
21. Nonlinear feedback stabilisation and stochastic disturbance suppression of actively Q-switched lasers
- Author
-
Tarra, Lukas, Deutschmann-Olek, Andreas, and Kugi, Andreas
- Subjects
Electrical Engineering and Systems Science - Systems and Control ,Nonlinear Sciences - Chaotic Dynamics ,Physics - Optics - Abstract
Actively Q-switched lasers are widely used tools which are required to produce stable output pulse energies for many applications. In this paper, a model-based control concept for actively Q-switched lasers is presented which stabilises their nonlinear pulse-to-pulse dynamics and rejects stochastic disturbances arising from amplified spontaneous emission. The feasibility of the control task is demonstrated to strongly depend on the design of the semi-active prelasing approach. In contrast to state-of-the-art hardware-based controllers, the proposed concept is flexible and cost-effective as it is not tailored to specific operation parameters., Comment: 6 pages, 5 figures, accepted for IFAC World Congress 2023 more...
- Published
- 2023
22. Optimal control of quasi-1D Bose gases in optical box potentials
- Author
-
Deutschmann-Olek, Andreas, Schrom, Katharina, Würkner, Nikolaus, Schmiedmayer, Jörg, Erne, Sebastian, and Kugi, Andreas
- Subjects
Electrical Engineering and Systems Science - Systems and Control ,Condensed Matter - Quantum Gases ,Quantum Physics - Abstract
In this paper, we investigate the manipulation of quasi-1D Bose gases that are trapped in a highly elongated potential by optimal control methods. The effective meanfield dynamics of the gas can be described by a one-dimensional non-polynomial Schr\"odinger equation. We extend the indirect optimal control method for the Gross-Pitaevskii equation by Winckel and Borzi (2008) to obtain necessary optimality conditions for state and energy cost functionals. This approach is then applied to optimally compress a quasi-1D Bose gase in an (optical) box potential, i.e., to find a so-called short-cut to adiabaticity, by solving the optimality conditions numerically. The behavior of the proposed method is finally analyzed and compared to simple direct optimization strategies using reduced basis functions. Simulations results demonstrate the feasibility of the proposed approach., Comment: 6 pages, 5 figures, 2 tables, accepted for IFAC World Congress 2023 more...
- Published
- 2023
23. XL-MIMO Channel Modeling and Prediction for Wireless Power Transfer
- Author
-
Deutschmann, Benjamin J. B., Wilding, Thomas, Graber, Maximilian, and Witrisal, Klaus
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Massive antenna arrays form physically large apertures with a beam-focusing capability, leading to outstanding wireless power transfer (WPT) efficiency paired with low radiation levels outside the focusing region. However, leveraging these features requires accurate knowledge of the multipath propagation channel and overcoming the (Rayleigh) fading channel present in typical application scenarios. For that, reciprocity-based beamforming is an optimal solution that estimates the actual channel gains from pilot transmissions on the uplink. But this solution is unsuitable for passive backscatter nodes that are not capable of sending any pilots in the initial access phase. Using measured channel data from an extremely large-scale MIMO (XL-MIMO) testbed, we compare geometry-based planar wavefront and spherical wavefront beamformers with a reciprocity-based beamformer, to address this initial access problem. We also show that we can predict specular multipath components (SMCs) based only on geometric environment information. We demonstrate that a transmit power of 1W is sufficient to transfer more than 1mW of power to a device located at a distance of 12.3m when using a (40x25) array at 3.8GHz. The geometry-based beamformer exploiting predicted SMCs suffers a loss of only 2dB compared with perfect channel state information. more...
- Published
- 2023
24. Uplink Joint Positioning and Synchronization in Cell-Free Deployments with Radio Stripes
- Author
-
Fascista, Alessio, Deutschmann, Benjamin J. B., Keskin, Musa Furkan, Wilding, Thomas, Coluccia, Angelo, Witrisal, Klaus, Leitinger, Erik, Seco-Granados, Gonzalo, and Wymeersch, Henk
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Radio stripes (RSs) is an emerging technology in beyond 5G and 6G wireless networks to support the deployment of cell-free architectures. In this paper, we investigate the potential use of RSs to enable joint positioning and synchronization in the uplink channel at sub-6 GHz bands. The considered scenario consists of a single-antenna user equipment (UE) that communicates with a network of multiple-antenna RSs distributed over a wide area. The UE is assumed to be unsynchronized to the RSs network, while individual RSs are time- and phase-synchronized. We formulate the problem of joint estimation of position, clock offset, and phase offset of the UE and derive the corresponding maximum-likelihood (ML) estimator, both with and without exploiting carrier phase information. To gain fundamental insights into the achievable performance, we also conduct a Fisher information analysis and inspect the theoretical lower bounds numerically. Simulation results demonstrate that promising positioning and synchronization performance can be obtained in cell-free architectures supported by RSs, revealing at the same time the benefits of carrier phase exploitation through phase-synchronized RSs. more...
- Published
- 2023
25. Optimizing optical potentials with physics-inspired learning algorithms
- Author
-
Calzavara, Martino, Kuriatnikov, Yevhenii, Deutschmann-Olek, Andreas, Motzoi, Felix, Erne, Sebastian, Kugi, Andreas, Calarco, Tommaso, Schmiedmayer, Jörg, and Prüfer, Maximilian
- Subjects
Condensed Matter - Quantum Gases ,Physics - Atomic Physics ,Physics - Optics - Abstract
We present our new experimental and theoretical framework which combines a broadband superluminescent diode (SLED/SLD) with fast learning algorithms to provide speed and accuracy improvements for the optimization of 1D optical dipole potentials, here generated with a Digital Micromirror Device (DMD). To characterize the setup and potential speckle patterns arising from coherence, we compare the superluminescent diode to a single-mode laser by investigating interference properties. We employ Machine Learning (ML) tools to train a physics-inspired model acting as a digital twin of the optical system predicting the behavior of the optical apparatus including all its imperfections. Implementing an iterative algorithm based on Iterative Learning Control (ILC) we optimize optical potentials an order of magnitude faster than heuristic optimization methods. We compare iterative model-based offline optimization and experimental feedback-based online optimization. Our methods provide a new route to fast optimization of optical potentials which is relevant for the dynamical manipulation of ultracold gases., Comment: 10 pages, 5 figures more...
- Published
- 2022
- Full Text
- View/download PDF
26. Attention-based Interpretable Regression of Gene Expression in Histology
- Author
-
Graziani, Mara, Marini, Niccolò, Deutschmann, Nicolas, Janakarajan, Nikita, Müller, Henning, and Martínez, María Rodríguez
- Subjects
Quantitative Biology - Quantitative Methods ,Computer Science - Machine Learning - Abstract
Interpretability of deep learning is widely used to evaluate the reliability of medical imaging models and reduce the risks of inaccurate patient recommendations. For models exceeding human performance, e.g. predicting RNA structure from microscopy images, interpretable modelling can be further used to uncover highly non-trivial patterns which are otherwise imperceptible to the human eye. We show that interpretability can reveal connections between the microscopic appearance of cancer tissue and its gene expression profiling. While exhaustive profiling of all genes from the histology images is still challenging, we estimate the expression values of a well-known subset of genes that is indicative of cancer molecular subtype, survival, and treatment response in colorectal cancer. Our approach successfully identifies meaningful information from the image slides, highlighting hotspots of high gene expression. Our method can help characterise how gene expression shapes tissue morphology and this may be beneficial for patient stratification in the pathology unit. The code is available on GitHub., Comment: Github Repo: https://github.com/maragraziani/interpretableWSItoRNAseq more...
- Published
- 2022
27. Iterative shaping of optical potentials for one-dimensional Bose-Einstein condensates
- Author
-
Deutschmann-Olek, Andreas, Tajik, Mohammadamin, Calzavara, Martino, Schmiedmayer, Jörg, Calarco, Tommaso, and Kugi, Andreas
- Subjects
Electrical Engineering and Systems Science - Systems and Control ,Condensed Matter - Quantum Gases ,Physics - Optics ,Quantum Physics - Abstract
The ability to manipulate clouds of ultra-cold atoms is crucial for modern experiments on quantum manybody systems and quantum thermodynamics as well as future metrological applications of Bose-Einstein condensate. While optical manipulation offers almost arbitrary flexibility, the precise control of the resulting dipole potentials and the mitigation of unwanted disturbances is quite involved and only heuristic algorithms with rather slow convergence rates are available up to now. This paper thus suggests the application of iterative learning control (ILC) methods to generate fine-tuned effective potentials in the presence of uncertainties and external disturbances. Therefore, the given problem is reformulated to obtain a one-dimensional tracking problem by using a quasicontinuous input mapping which can be treated by established ILC methods. Finally, the performance of the proposed concept is illustrated in a simulation scenario., Comment: To appear in Proceedings of the 61st IEEE Conference on Decision and Control (CDC) more...
- Published
- 2022
- Full Text
- View/download PDF
28. Is Attention Interpretation? A Quantitative Assessment On Sets
- Author
-
Haab, Jonathan, Deutschmann, Nicolas, and Martínez, Maria Rodríguez
- Subjects
Computer Science - Machine Learning - Abstract
The debate around the interpretability of attention mechanisms is centered on whether attention scores can be used as a proxy for the relative amounts of signal carried by sub-components of data. We propose to study the interpretability of attention in the context of set machine learning, where each data point is composed of an unordered collection of instances with a global label. For classical multiple-instance-learning problems and simple extensions, there is a well-defined "importance" ground truth that can be leveraged to cast interpretation as a binary classification problem, which we can quantitatively evaluate. By building synthetic datasets over several data modalities, we perform a systematic assessment of attention-based interpretations. We find that attention distributions are indeed often reflective of the relative importance of individual instances, but that silent failures happen where a model will have high classification performance but attention patterns that do not align with expectations. Based on these observations, we propose to use ensembling to minimize the risk of misleading attention-based explanations., Comment: 11 pages, 20 figures. Presented at the XKDD 2022 workshop more...
- Published
- 2022
29. A stochastic nonlinear model of the dynamics of actively Q-switched lasers
- Author
-
Tarra, Lukas, Deutschmann-Olek, Andreas, Stummer, Vinzenz, Flöry, Tobias, Baltuska, Andrius, and Kugi, Andreas
- Subjects
Physics - Optics ,Nonlinear Sciences - Chaotic Dynamics - Abstract
In this paper, we present a novel stochastic and spatially lumped multi-mode model to describe the nonlinear dynamics of actively Q-switched lasers and random perturbations due to amplified spontaneous emission. This model will serve as a basis for the design of (nonlinear) control and estimation strategies and thus a high value is set on its computational efficiency. Therefore, a common traveling-wave model is chosen as a starting point and a number of model-order reduction steps are performed. As a result, a set of nonlinear ordinary differential equations for the dynamic behavior of the laser during a switching cycle is obtained. A semi-analytic solution of these differential equations yields expressions for the population inversion after a switching cycle and for the output energy, which are then used to formulate a nonlinear discrete-time model for the pulse-to-pulse dynamics. Simulation studies including models with different levels of complexity and first experimental results demonstrate the feasibility of the proposed approach. more...
- Published
- 2022
- Full Text
- View/download PDF
30. Location-based Initial Access for Wireless Power Transfer with Physically Large Arrays
- Author
-
Deutschmann, Benjamin J. B., Wilding, Thomas, Larsson, Erik G., and Witrisal, Klaus
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Radio frequency (RF) wireless power transfer (WPT) is a promising technology for 6G use cases. It enables a massive, yet sustainable deployment of batteryless energy neutral (EN) devices at unprecedented scale. Recent research on 6G is exploring high operating frequencies up to the THz spectrum, where antenna arrays with large apertures are capable of forming narrow, "laser-like" beams. At sub-10 GHz frequencies, physically large antenna arrays are considered that are operating in the array near field. Transmitting spherical wavefronts, power can be focused in a focal point rather than a beam, which allows for efficient and radiation-safe WPT. We formulate a multipath channel model comprising specular components and diffuse scattering to find the WPT power budget in a realistic indoor scenario. Specular components can be predicted by means of a geometric model. This is used to transmit power via multiple beams simultaneously, increasing the available power budget and expanding the initial access distance. We show that exploiting this "beam diversity" reduces the required fading margin for the initial access to EN devices., Comment: This work has been submitted to the IEEE for possible publication more...
- Published
- 2022
- Full Text
- View/download PDF
31. Performance of QUIC Implementations Over Geostationary Satellite Links
- Author
-
Endres, Sebastian, Deutschmann, Jörg, Hielscher, Kai-Steffen, and German, Reinhard
- Subjects
Computer Science - Networking and Internet Architecture ,Computer Science - Performance - Abstract
QUIC was recently standardized as RFC 9000, but the performance of QUIC over geostationary satellite links is problematic due to the non-applicability of Performance Enhancing Proxies. As of today, there are more than a dozen of different QUIC implementations. So far performance evaluations of QUIC over satellite links were limited to specific QUIC implementations. By deploying a modified version of the IETF QUIC-Interop-Runner, this paper evaluates the performance of multiple QUIC implementations over multiple geostationary satellite links. This includes two emulated ones (with and without packet loss) and two real ones. The results show that the goodput achieved with QUIC over geostationary satellite links is very poor in general, and especially poor when there is packet loss. Some implementations fail completely and the performance of the other implementations varies greatly. The performance depends on both client and server implementation. more...
- Published
- 2022
32. Real-time optimal quantum control of mechanical motion at room temperature
- Author
-
Magrini, Lorenzo, Rosenzweig, Philipp, Bach, Constanze, Deutschmann-Olek, Andreas, Hofer, Sebastian G., Hong, Sungkun, Kiesel, Nikolai, Kugi, Andreas, and Aspelmeyer, Markus
- Subjects
Quantum Physics ,Physics - Atomic Physics ,Physics - Optics - Abstract
The ability to accurately control the dynamics of physical systems by measurement and feedback is a pillar of modern engineering. Today, the increasing demand for applied quantum technologies requires to adapt this level of control to individual quantum systems. Achieving this in an optimal way is a challenging task that relies on both quantum-limited measurements and specifically tailored algorithms for state estimation and feedback. Successful implementations thus far include experiments on the level of optical and atomic systems. Here we demonstrate real-time optimal control of the quantum trajectory of an optically trapped nanoparticle. We combine confocal position sensing close to the Heisenberg limit with optimal state estimation via Kalman filtering to track the particle motion in phase space in real time with a position uncertainty of 1.3 times the zero point fluctuation. Optimal feedback allows us to stabilize the quantum harmonic oscillator to a mean occupation of $n=0.56\pm0.02$ quanta, realizing quantum ground state cooling from room temperature. Our work establishes quantum Kalman filtering as a method to achieve quantum control of mechanical motion, with potential implications for sensing on all scales. In combination with levitation, this paves the way to full-scale control over the wavepacket dynamics of solid-state macroscopic quantum objects in linear and nonlinear systems. more...
- Published
- 2020
- Full Text
- View/download PDF
33. Cognitive Production Systems: A Mapping Study
- Author
-
Deutschmann, Bastian, Ghofrani, Javad, and Reichelt, Dirk
- Subjects
Computer Science - Multiagent Systems ,Computer Science - Human-Computer Interaction - Abstract
Production plants today are becoming more and more complicated through more automation and networking. It is becoming more difficult for humans to participate, due to higher speed and decreasing reaction time of these plants. Tendencies to improve production systems with the help of cognitive systems can be identified. The goal is to save resources and time. This mapping study gives an insight into the domain, categorizes different approaches and estimates their progress. Furthermore, it shows achieved optimizations and persisting problems and barriers. These representations should make it easier in the future to address concrete problems in this research field. Human-Machine Interaction and Knowledge Gaining/Sharing represent the largest categories of the domain. Most often, a gain in efficiency and maximized effectiveness can be achieved as optimization. The most common problem is the missing or only difficult generalization of the presented concepts., Comment: 10 pages more...
- Published
- 2020
34. Quark mass effects in two-loop Higgs amplitudes
- Author
-
Anastasiou, Charalampos, Deutschmann, Nicolas, and Schweitzer, Armin
- Subjects
High Energy Physics - Phenomenology - Abstract
We provide two two-loop amplitudes relevant for precision Higgs physics. The first is the two-loop amplitude for Higgs boson production through gluon fusion with exact dependence on the top quark mass up to squared order in the dimensional regulator $\epsilon$. The second result we provide is the two-loop amplitude for the decay of a Higgs boson into a pair of massive bottom quarks through the Higgs-to-gluon coupling in the infinite top mass limit. Both amplitudes are computed by finding canonical bases of master integrals, which we evaluate explicitly in terms of harmonic polylogarithms. We obtain the bare, renormalized and IR-subtracted amplitude and provide the results in terms of building blocks suitable to changing renormalization schemes., Comment: ancillary files in folder: 'source/ancillary_material' more...
- Published
- 2020
- Full Text
- View/download PDF
35. Momentum mappings for subtractions at higher orders in QCD
- Author
-
Del Duca, Vittorio, Deutschmann, Nicolas, and Lionetti, Simone
- Subjects
High Energy Physics - Phenomenology - Abstract
Subtraction schemes provide a systematic way to compute fully-differential cross sections beyond the leading order in the strong coupling constant. These methods make singular real-emission corrections integrable in phase space by the addition of suitable counterterms. Such counterterms may be defined using momentum mappings, which are parametrisations of the phase space that factorise the variables that describe the particles becoming unresolved in some infrared or collinear limit from the variables that describe an on-shell phase space for the resolved particles. In this work, we review existing momentum mappings in a unified framework and introduce new ones for final-collinear and soft counterterms. The new mappings work in the presence of massive particles and with an arbitrary number of soft particles or of clusters of collinear particles, making them fit for subtraction methods at any order in perturbation theory. The new mapping for final-collinear counterterms is also used to elucidate relations among existing final-collinear mappings. more...
- Published
- 2019
- Full Text
- View/download PDF
36. First fully kinetic three-dimensional simulation of the AWAKE baseline scenario
- Author
-
Moschüring, N., Lotov, K. V., Bamberg, K., Deutschmann, F., and Ruhl, H.
- Subjects
Physics - Computational Physics ,Physics - Accelerator Physics ,Physics - Plasma Physics - Abstract
The "Advanced Proton Driven Plasma Wakefield Acceleration Experiment" (AWAKE) aims to accelerate leptons via proton-beam-driven wakefield acceleration. It comprises extensive numerical studies as well as experiments at the CERN laboratory. The baseline scenario incorporates a plasma volume of approximately $62\,\mathrm{cm}^3$. The plasma wavelength is about $1.25\,\mathrm{mm}$ and needs to be adequately resolved, using a minimum of $130$ points per plasma wavelength, in order to accurately reproduce the physics. The baseline scenario incorporates the proton beam micro-bunching, the concurrent non-linear wakefield growth as well as the off-axis electron beam injection, trapping and acceleration. We present results for the first three-dimensional simulation of this baseline scenario with a full model, using a sufficient resolution. The simulation consumed about $22\,\mathrm{Mch}$ of computer resources and scaled up to 32768 cores, thanks to a multitude of adaptions, improvements and optimization of the simulation code PSC. Through this large-scale simulation effort we were able to verify the results of reduced-model simulations as well as identify important novel effects during the electron injection process., Comment: 11 pages, 6 figures, 2 tables, results presented at the Laser-Plasma Accelerator Workshop 2019, submitted to Plasma Physics and Controlled Fusion more...
- Published
- 2019
- Full Text
- View/download PDF
37. Top-Yukawa contributions to bbH production at the LHC
- Author
-
Deutschmann, Nicolas, Maltoni, Fabio, Wiesemann, Marius, and Zaro, Marco
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
We study the production of a Higgs boson in association with bottom quarks ($b\bar{b}H$) in hadronic collisions at the LHC, including the different contributions stemming from terms proportional to the top-quark Yukawa coupling ($y_t^2$), to the bottom-quark one ($y_b^2$), and to their interference ($y_b y_t$). Our results are accurate to next-to-leading order in QCD, employ the four-flavour scheme and the (Born-improved) heavy-top quark approximation. We find that next-to-leading order corrections to the $y_t^2$ component are sizable, making it the dominant production mechanism for associated $b\bar{b}H$ production in the Standard Model and increasing its inclusive rate by almost a factor of two. By studying final-state distributions of the various contributions, we identify observables and selection cuts that can be used to select the various components and to improve the experimental sensitivity of $b\bar{b}H$ production on the bottom-quark Yukawa coupling., Comment: 43 pages, 13 figures, 2 tables; matches the version published on JHEP, with footnote 6 updated more...
- Published
- 2018
- Full Text
- View/download PDF
38. Gluon-fusion Higgs production in the Standard Model Effective Field Theory
- Author
-
Deutschmann, Nicolas, Duhr, Claude, Maltoni, Fabio, and Vryonidou, Eleni
- Subjects
High Energy Physics - Phenomenology - Abstract
We provide the complete set of predictions needed to achieve NLO accuracy in the Standard Model Effective Field Theory at dimension six for Higgs production in gluon fusion. In particular, we compute for the first time the contribution of the chromomagnetic operator $ \bar Q_L \Phi \sigma q_R G$ at NLO in QCD, which entails two-loop virtual and one-loop real contributions, as well as renormalisation and mixing with the Yukawa operator $\Phi^\dagger \Phi\, \bar Q_L \Phi q_R$ and the gluon-fusion operator $\Phi^\dagger \Phi\, GG$. Focusing on the top-quark-Higgs couplings, we consider the phenomenological impact of the NLO corrections in constraining the three relevant operators by implementing the results into the MadGraph5_aMC@NLO framework. This allows us to compute total cross sections as well as to perform event generation at NLO that can be directly employed in experimental analyses., Comment: 30 pages. This version includes the corrections of our Erratum published in JHEP (2018) 2018: 159 more...
- Published
- 2017
- Full Text
- View/download PDF
39. On the information content of discrete phylogenetic characters
- Author
-
Bordewich, Magnus, Deutschmann, Ina Maria, Fischer, Mareike, Kasbohm, Elisa, Semple, Charles, and Steel, Mike
- Subjects
Quantitative Biology - Populations and Evolution - Abstract
Phylogenetic inference aims to reconstruct the evolutionary relationships of different species based on genetic (or other) data. Discrete characters are a particular type of data, which contain information on how the species should be grouped together. However, it has long been known that some characters contain more information than others. For instance, a character that assigns the same state to each species groups all of them together and so provides no insight into the relationships of the species considered. At the other extreme, a character that assigns a different state to each species also conveys no phylogenetic signal. In this manuscript, we study a natural combinatorial measure of the information content of an individual character and analyse properties of characters that provide the maximum phylogenetic information, particularly, the number of states such a character uses and how the different states have to be distributed among the species or taxa of the phylogenetic tree., Comment: 16 pages, 7 figures. Final version has now appeared in Journal of Mathematical Biology (December 2017) https://link.springer.com/article/10.1007/s00285-017-1198-2 more...
- Published
- 2017
40. Current LHC Constraints on Minimal Universal Extra Dimensions
- Author
-
Deutschmann, Nicolas, Flacke, Thomas, and Kim, Jong Soo
- Subjects
High Energy Physics - Phenomenology - Abstract
In this letter, we present LHC limits on the minimal universal extra dimension (MUED) model from LHC Run 1 data and current limits from searches of the ongoing Run 2. Typical collider signals of the Kaluza-Klein (KK) states mimic generic degenerate supersymmetry (SUSY) missing transverse momentum signatures since the excited KK particles cascade decay to jets, leptons and the lightest KK particle which is stable due to KK parity and thus evades detection. We test the parameter space against a large number of supersymmetry based missing energy searches implemented in the public code CheckMATE. We demonstrate the complementarity of employing various searches which target a large number of final state signatures, and we derive the most up to date limits on the MUED parameter space from 13 TeV SUSY searches., Comment: 8 pages, 3 figures, 2 tables; v2: typos fixed, references added; matches version published in Phys.Lett.B more...
- Published
- 2017
- Full Text
- View/download PDF
41. Compact Extra Dimensions in Quantum Mechanics
- Author
-
Deutschmann, Nicolas
- Subjects
Physics - General Physics - Abstract
Extra-dimensions are a common topic in popular descriptions of theoretical physics with which undergraduate student most often have no contact in physics courses. This paper shows how students could be introduced to this topic by presenting an approach to two basic consequences of the presence of compact extra-dimensions based on undergraduate-level physics. The insensibility of low-energy physics to compact extra dimensions is illustrated in the context of non-relativistic quantum mechanics and the prediction of Kaluza-Klein excitations of particles is discussed in the framework of relativistic wave-equations. An exercise that could be used as a follow-up to the "particle in a box" is proposed., Comment: 6 pages, 2 figures more...
- Published
- 2016
42. Towards Kaluza-Klein Dark Matter on Nilmanifolds
- Author
-
Andriot, David, Cacciapaglia, Giacomo, Deandrea, Aldo, Deutschmann, Nicolas, and Tsimpis, Dimitrios
- Subjects
High Energy Physics - Theory ,High Energy Physics - Phenomenology ,Mathematics - Spectral Theory - Abstract
We present a first study of the field spectrum on a class of negatively-curved compact spaces: nilmanifolds or twisted tori. This is a case where analytical results can be obtained, allowing to check numerical methods. We focus on the Kaluza-Klein expansion of a scalar field. The results are then applied to a toy model where a natural Dark Matter candidate arises as a stable massive state of the bulk scalar., Comment: 32 pages, 8 figures; v2: few additions, published version more...
- Published
- 2016
- Full Text
- View/download PDF
43. Dark matter and localised fermions from spherical orbifolds?
- Author
-
Cacciapaglia, Giacomo, Deandrea, Aldo, and Deutschmann, Nicolas
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Theory - Abstract
We study a class of six-dimensional models based on positive curvature surfaces (spherical 2-orbifolds) as extra-spaces. Using the Newman-Penrose formalism, we discuss the particle spectrum in this class of models. The fermion spectrum problem, which has been addressed with flux compactifications in the past, can be avoided using localised fermions. In this framework, we find that there are four types of geometry compatible with the existence of a stable dark matter candidate and we study the simplest case in detail. Using the complementarity between collider resonance searches and relic density constraints, we show that this class of models is under tension, unless the model lies in a funnel region characterised by a resonant Higgs s-channel in the dark matter annihilation., Comment: 38 pages, 7 figures more...
- Published
- 2016
- Full Text
- View/download PDF
44. A structured approach for the evaluation, validation and implementation of NAT-based mycoplasma detection methods
- Author
-
A Montero Julian, Felix, primary, Corrado, Antoinetta, additional, Tur Garcia, Eva, additional, Goodier, Rob, additional, McMutrie, Donna, additional, Hooper, Scott, additional, Jorgensen, Anette, additional, McAlister, Morven, additional, Deutschmann, Sven, additional, McCarthy, Kevin, additional, Bonnevay, Thierry, additional, Dormeyer, Miriam, additional, and Brewer, Michael, additional more...
- Published
- 2023
- Full Text
- View/download PDF
45. The Spatial Structure of Transnational Human Activity
- Author
-
Deutschmann, Emanuel
- Subjects
Computer Science - Social and Information Networks ,Physics - Physics and Society - Abstract
Recent studies have shown that the spatial structures of animal displacements and local-scale human motion follow L\'{e}vy flights. Whether transnational human activity (THA) also exhibits such a pattern has however not been thoroughly examined as yet. To fill this gap, this article examines the planet-scale spatial structure of THA (a) across eight types of mobility and communication and (b) in its development over time. Combining data from various sources, it is shown that the spatial structure of THA can indeed be approximated by L\'{e}vy flights with heavy tails that obey power laws. Scaling exponent and power-law fit differ by type of THA, being highest in refuge-seeking and tourism and lowest in student exchange. Variance in the availability of resources and opportunities for satisfying associated needs appears to explain these differences. Over time, the L\'{e}vy-flight pattern remains intact and remarkably stable, contradicting the popular idea that socio-technological trends lead to a "death of distance." Longitudinal change occurs only in some types of THA and predominantly at short distances, indicating regional shifts rather than globalization. more...
- Published
- 2015
46. A statistical noise model for a class of Physically Unclonable Functions
- Author
-
Hackl, Benjamin, Kurz, Daniel, Heuberger, Clemens, Pilz, Jürgen, and Deutschmann, Martin
- Subjects
Statistics - Applications ,62P30 (Primary), 62F15, 68P30, 94A60, 94B70 (Secondary) ,G.3 ,B.8.1 - Abstract
The interest in "Physically Unclonable Function"-devices has increased rapidly over the last few years, as they have several interesting properties for system security related applications like, for example, the management of cryptographic keys. Unfortunately, the output provided by these devices is noisy and needs to be corrected for these applications. Related error correcting mechanisms are typically constructed on the basis of an equal error probability for each output bit. This assumption does not hold for Physically Unclonable Functions, where varying error probabilities can be observed. This results in a generalized binomial distribution for the number of errors in the output. The intention of this paper is to discuss a novel Bayesian statistical model for the noise of an especially wide-spread class of Physically Unclonable Functions, which properly handles the varying output stability and also reflects the different noise behaviors observed in a collection of such devices. Furthermore, we compare several different methods for estimating the model parameters and apply the proposed model to concrete measurements obtained within the CODES research project in order to evaluate typical correction and stabilization approaches. more...
- Published
- 2014
47. Multi-tops at the LHC
- Author
-
Deandrea, Aldo and Deutschmann, Nicolas
- Subjects
High Energy Physics - Phenomenology - Abstract
The experiments at the LHC are searching for many different final states that can hint to the presence of new physics beyond the Standard Model. One of the most interesting and promising sectors for these searches is that of the top quark, for both theoretical and phenomenological reasons linked to its large mass and to its possible special role in the electroweak symmetry breaking sector. We suggest that multi-top events, beyond the standard $t$-$\bar t$ and four top searches, can bring further insight in constraining and discovering physics beyond the Standard Model, taking advantage of experimental techniques similar to those used in present top-quark analyses. This is relevant both for the next data taking runs at the LHC and even more at higher luminosity and higher energy collider options, which are discussed for future LHC upgrades and future accelerators. In particular we consider six top and eight top final states, discussing the generic colour representations for beyond the Standard Model particles giving rise to those final state. We also discuss the limits which can be extracted by using the present analyses sensitive to four top final states, as well as the potential bounds from new searches we propose to experimental collaborations as an alternative., Comment: 16 pages more...
- Published
- 2014
- Full Text
- View/download PDF
48. Identifying Identity: Using Second Life in the Teaching of Sociolinguistics for the Rasing of Gender Awareness
- Author
-
European Association for Computer-Assisted Language Learning (EUROCALL) (United Kingdom), Deutschmann, Mats, and Steinvall, Anders
- Abstract
This paper presents further innovative use of virtual worlds under the pilot stages of ASSIS (A Second Step in Second Life), a project funded by Umea University. One of the aims of the project is to make use of the affordances offered by Second Life in order to raise sociolinguistic language awareness among teacher trainees and other students studying courses in sociolinguistics. Several experiments were conducted where creative use of the avatar in combination with so-called "voice morphing" (a tool which allows the voice of the speaker to be distorted so that a male speaker can sound more feminine and vice versa) allowed students to enter the virtual world incognito in order to "experience" a different linguistic identity. Activities were conducted in cross-cultural settings involving students from Sweden and Chile. The paper presents the initial stages of development of a model for how language awareness issues can be internalised through first-hand experience in virtual worlds. (Contains 3 footnotes.) more...
- Published
- 2010
49. Simulating spin-3/2 particles at colliders
- Author
-
Christensen, Neil D., de Aquino, P., Deutschmann, N., Duhr, C., Fuks, B., Garcia-Cely, C., Mattelaer, O., Mawatari, K., Oexl, B., and Takaesu, Y.
- Subjects
High Energy Physics - Phenomenology - Abstract
Support for interactions of spin-3/2 particles is implemented in the FeynRules and ALOHA packages and tested with the MadGraph 5 and CalcHEP event generators in the context of three phenomenological applications. In the first, we implement a spin-3/2 Majorana gravitino field, as in local supersymmetric models, and study gravitino and gluino pair-production. In the second, a spin-3/2 Dirac top-quark excitation, inspired from compositness models, is implemented. We then investigate both top-quark excitation and top-quark pair-production. In the third, a general effective operator for a spin-3/2 Dirac quark excitation is implemented, followed by a calculation of the angular distribution of the s-channel production mechanism., Comment: 20 pages, 7 figures more...
- Published
- 2013
- Full Text
- View/download PDF
50. TR Alternative adventititous agents detection methods in biopharmaceuticals
- Author
-
Deutschmann, Sven, primary, Franz-Riethdorf, Margit, additional, and Green, Bela, additional
- Published
- 2022
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.