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The DArk Matter Particle Explorer (DAMPE) is a satellite-borne particle detector for measurements of high-energy cosmic rays and {\gamma}-rays. DAMPE has been operating smoothly in space for more than 8 years since launch on December 17, 2015. The trigger logic of DAMPE is designed according to the deposited energy information recorded by the calorimeter. The precise calibration of the trigger thresholds and their long-term evolutions are very important for the scientific analysis of DAMPE. In this work, we develop a new method for the threshold calibration, considering the influence from the electronic noise, and obtain the long-term evolutions of the trigger thresholds. The average increase rate of the trigger thresholds for the first 4 layers of the calorimeter is found to be about 0.9% per year, resulting in variations of the high-energy trigger efficiency of cosmic ray electrons by about -5% per year at 2 GeV and less than about -0.05% above 30 GeV., Comment: 11 pages, 11 figures

Thermal transport is a fundamental mechanism of energy transfer process quite distinct from wave propagation phenomena. It can be manipulated well beyond the possibilities offered by natural materials with a new generation of artificial metamaterials: thermal metamaterials. Topological physics, a focal point in contemporary condensed matter physics, is closely intertwined with thermal metamaterials in recent years. Inspired by topological photonics and topological acoustics in wave metamaterials, a new research field emerged recently, which we dub `topological thermotics', which encompasses three primary branches: topological thermal conduction, convection, and radiation. For topological thermal conduction, we discuss recent advances in both 1D and higher-dimensional thermal topological phases. For topological thermal convection, we discuss the implementation of thermal exceptional points with their unique properties and non-Hermitian thermal topological states. Finally, we review the most recent demonstration of topological effects in the near-field and far-field radiation. Anticipating future developments, we conclude by discussing potential directions of topological thermotics, including the expansion into other diffusion processes such as particle dynamics and plasma physics, and the integration with machine learning techniques., Comment: This perpective summarizes the topological physics in thermal metamaterials and proposes a new research field, "topological thermotics"

We derive self-consistent constraint conditions for collision terms in quantum kinetic theory within Wigner function formalism. We present simple specific solutions for the collision terms in quantum kinetic theory which is compatible with these constraints. We obtain the self-consistent quantum kinetic theory at relaxation-time approximation, with which we discuss spin polarization effects and electric charge separation effects in relativistic heavy-ion collisions., Comment: 24 pages

We have derived the Wigner equations at global equilibrium with constant vorticity but space-time dependent electromagnetic fields up to second order in semiclassical expansion. We obtain the new second-order contributions to the charge currents and energy-momentum tensor from the varying electromagnetic fields. We also compute the new corrections to the spin polarization pesudo-vector from both contant and varying electromagnetic fields. We also find that the space-time dependent electromagnetic field provides a tighter constraint on the solutions of Wigner functions in global equilibrium compared with constant electromagnetic field., Comment: 20 pages

High-brightness coherent light source is at the heart of optical technology and yet challenging to achieve. Here, we propose an unconventional approach that utilizes the "forbidden chemical" in optical thermodynamics to convert any incoming light beam into a high-brightness, high-spatial-coherence light beam in multimode nonlinear optical waveguide systems, in contrast to evaporative cooling in cold atoms where the brightness is instead reduced. This approach is powered by the fact that light in nonlinear multimode structures undergoes an irreversible thermalization process triggered by its own photon-photon interactions. Moreover, the key characteristics in statistical mechanics, the optical temperature and chemical potential can be widely tuned in photonic systems. As such, when the chemical potential of an optical reservoir is designed to locate at the forbidden band of the probe bosonic system, it can never reach thermal equilibrium with the probe hence endlessly pumping the probe system towards an enhanced brightness and spatial coherence. This amplified cooling of light beam is revealed via both Onsager's irreversible thermodynamics theory and numerical simulations. Akin to this effect, the inverse photonic transport currents emerge due to the negative off-diagonal Onsager coefficients. We demonstrate the feasibility of the amplified beam cooling using a coupled multimode optical waveguide system and show that after 800 rounds of amplified cooling, the optical power of an incoming beam is enhanced by 16 times, meanwhile the fundamental mode occupancy is increased to 90%. These findings unveil an anomalous optical phenomenon and a new route toward high-quality light sources.

Integrated nanophotonic biosensors offer a promising route toward future biomedical detection applications that may enable inexpensive, portable, and sensitive diagnosis of diseases with a small amount of biological samples for convenient early-stage screening of fatal diseases. However, the current photonic biosensor designs are not suitable for highly integrated and multiplexing device architectures that can achieve the detection of complex combinations of many biomarkers. Here, we propose a topological scheme for the integration of miniature biosensors in photonic crystal chips that can meet the above requirement. Using photonic topological edge states as robust one-dimensional waveguides that connect many photonic biosensors, we propose here the topologically integrated photonic biosensor circuits. We demonstrate that the performance of the topologically integrated photonic biosensors is much more robust against disorders than that of the photonic biosensors connected by the normal photonic waveguides, due to the robust transport of photons along the edge channel. Since disorders arising from the fabrication imperfection and the random distribution of the biomarkers are inevitable in genuine devices, resilience against disorders is a necessity for on-chip integration of biosensors. The topological scheme proposed here thus opens a promising path toward reliable integration of photonic biosensors for next-generation biomedical applications.

We propose a conceptual device for multiplexed biosensor in a photonic crystal chip based on the Su-Schrieffer-Heeger mechanism. Remarkably, the proposed biosensor can identify three distinct disease markers through a single-shot photon transmission measurement, due to the couplings among the three Su-Schrieffer-Heeger boundary modes in the photonic crystal. Our biosensor design is more robust against defects and disorders inevitable in real-life device applications than previous designs. Such robustness is invaluable for achieving efficient, reliable, and integrated biosensing based on nanophotonic systems. We further demonstrate that various combinations of disease markers can be recognized via the photon transmission spectrum, unveiling a promising route toward high performance advanced biosensing for future biomedical technology.

Going beyond the conventional theory, non-Abelian band topology uncovers the global quantum geometry of Bloch bands with multiple gaps and thus unveil a new paradigm for topological physics. However, to date, all non-Abelian topological materials are restricted to systems with time-reversal symmetry (T). Here, starting from a Kagome lattice inspired by Haldane model and designer gyromagnetic photonic crystals (PhCs), we show that T breaking can lead to rich non-Abelian topological physics, particularly the emergence of multigap antichiral edge states. Simply changing the magnetic flux of the Kagome lattice, or in-situ tuning the local magnetic field of the gyromagnetic PhCs, can lead to the unconventional creation, braiding, merging, and splitting of non-Abelian charged band nodes, alongside with the direct manipulation of the multigap antichiral edge states. Particularly, the quadratic point can be split into four Dirac points, a phenomenon unique in T-broken systems. Our theoretical and experimental findings will inspire a new direction in the study of non-Abelian physics in T-broken systems and open an unprecedent pathway for topological manipulation of electromagnetic waves.

Silicon strip detectors have been widely utilized in space experiments for gamma-ray and cosmic-ray detections thanks to their high spatial resolution and stable performance. For a silicon micro-strip detector, the Monte Carlo simulation is recognized as a practical and cost-effective approach to verify the detector performance. In this study, a technique for the simulation of the silicon micro-strip detector with the $\rm Allpix^{2}$ framework is developed. By incorporating the electric field into the particle transport simulation based on Geant4, this framework could precisely emulate the carrier drift in the silicon micro-strip detector. The simulation results are validated using the beam test data as well as the flight data of the DAMPE experiment, which suggests that the $\rm Allpix^{2}$ framework is a powerful tool to obtain the performance of the silicon micro-strip detector.

Moir\'e related physics in twisted bilayer two-dimensional (2D) materials has attracted widespread interest in condensed matter physics. Simulation of moir\'e related physics in cold atom platform is expected to outperform the 2D materials thanks to its advantage of higher tunablility. Here, we point out, the cold atom platform enables a new mechanism of moir\'e lattice formation, with intrinsic "dynamical" character arising from interlayer interaction, in contrast to conventional moir\'e lattice induced by "static" ways such as single-particle interlayer tunneling or external controls. Specifically, we consider a twisted bilayer Bose-Hubbard model with vanishing interlayer tunneling, and the bilayer is solely coupled through interlayer interaction that originates from contact interaction of atoms. We find that this system hosts a plethora of novel phases unique to this dynamical lattice, including a variety of Mott insulator (MI) and superfluid (SF) phases either preserving or breaking moir\'e lattice symmetry, phases with one layer in SF and the other in MI, "interlocked" MI, and self-localized phases at commensurate twist angles, which exhibits the characteristics of Bose glass and quasi-many-body localization in the absence of (quasi)disorder or quasicrystalline lattices. Our prediction can be readily observed in current experimental setup of twisted bilayer optical lattices, opening up new avenues for exploring the rich physics of dynamical moir\'e systems in cold atoms., Comment: 4.5 pages (3 figures) + supplemental material (1 figure)

The nature of dark energy is one of the most outstanding problems in physical science, and various theories have been proposed. It is therefore essential to directly verify or rule out these theories experimentally. However, despite substantial efforts in astrophysical observations and laboratory experiments, previous tests have not yet acquired enough accuracy to provide decisive conclusions as to the validity of these theories. Here, using a diamagnetically levitated force sensor, we carry out a test on one of the most compelling explanations for dark energy to date, namely the Chameleon theory, an ultra-light scalar field with screening mechanisms, which couples to normal-matter fields and leaves a detectable fifth force. Our results extend previous results by nearly two orders of magnitude to the entire physical plausible parameter space of cosmologically viable chameleon models. We find no evidence for such a fifth force. Our results decisively rule out the basic chameleon model as a candidate for dark energy. Our work, thus, demonstrates the robustness of laboratory experiments in unveiling the nature of dark energy in the future. The methodology developed here can be further applied to study a broad range of fundamental physics.

Nonlinear multimode optical systems have attracted substantial attention due to their rich physical properties. Complex interplay between the nonlinear effects and mode couplings makes it difficult to understand the collective dynamics of photons. Recent studies show that such collective phenomena can be effectively described by a Rayleigh-Jeans thermodynamics theory which is a powerful tool for the study of nonlinear multimode photonic systems. These systems, in turn, offer a compelling platform for investigating fundamental issues in statistical physics, attributed to their tunability and the ability to access negative temperature regimes. However, to date, a theory for the nonequilibrium transport and fluctuations is yet to be established. Here, we employ the full counting statistics theory to study the nonequilibrium transport of particle and energy in nonlinear multimode photonic systems in both positive and negative temperature regimes. Furthermore, we discover that in situations involving two reservoirs of opposite temperatures and chemical potentials, an intriguing phenomenon known as the loop current effect can arise, wherein the current in the positive energy sector runs counter to that in the negative energy sector. In addition, we numerically confirm that the fluctuation theorem remains applicable in optical thermodynamics systems across all regimes, from positive temperature to negative ones. Our findings closely align with numerical simulations based on first-principles nonlinear wave equations. Our work seeks to deepen the understanding of irreversible non-equilibrium processes and statistical fluctuations in nonlinear many-body photonic systems which will enhance our grasp of collective phenomena of photons and foster a fruitful intersection between optics and statistical physics., Comment: All comments are welcome

The puckered lattice geometry, along with $p$-orbitals is often overlooked in the study of topological physics. Here, we investigate the higher-order topology of the $p_{x,y}$-orbital bands in acoustic metamaterials using a simplified two-dimensional phosphorene lattice which possesses a puckered structure. Notably, unlike the $s$-orbital bands in planar lattices, the unique higher-order topology observed here is specific to $p$-orbitals and the puckered geometry due to the unusual hopping patterns induced by them. {Using acoustic pump-probe measurements in metamaterials}, we confirm the emergence of the edge and corner states arising due to the unconventional higher-order topology. We reveal the uniqueness of the higher-order topological physics here via complimentary tight-binding calculations, finite-element simulations, and acoustic experiments. We analyze the underlying physics of the special properties of the edge and corner states in the puckered lattice acoustic metamaterials from the picture of Wannier orbitals. Our work sheds light on the intriguing physics of $p$-orbital topological physics in puckered lattices and acoustic metamaterials which lead to unconventional topological boundary states. \end{abstract}, Comment: Accepted by Phys. Rev. B

Non-Hermitian physics has added new ingredients to topological physics, leading to the rising frontier of non-Hermitian topological phases. In this study, we investigate Chern insulator phases emerging from non-Hermitian kagome models with non-reciprocal and pure imaginary next-nearest neighbor hoppings. In the presence or absence of $C_3$ rotation symmetry, hybrid topological-skin effects are explored through the identification of distinct corner skin modes in different energy regions within two band gaps. By employing the dynamical analysis, the underlying physics is revealed from the non-Hermitian skin effects associated with the chiral edge states, leading to diverse non-Hermitian bulk-boundary responses. The simplicity of these kagome models and their rich emergent topological phenomena suggest that they are appealing candidates for studying non-Hermitian topological phases. We further discuss the possible realizations of these models in non-Hermitian metamaterials.

Let $\mu$ be a positive Borel measure and $T_\mu$ be the bounded Toeplitz operator induced by $\mu$ on the Bergman or Fock space. In this paper, we mainly investigate the invertibility of the Toeplitz operator $T_\mu$ and the Douglas question on the Bergman and Fock spaces. In the Bergman-space setting, we obtain several necessary and sufficient conditions for the invertibility of $T_\mu$ in terms of the Berezin transform of $\mu$ and the reverse Carleson condition in two classical cases: (1) $\mu$ is absolutely continuous with respect to the normalized area measure on the open unit disk $\mathbb D$; (2) $\mu$ is the pull-back measure of the normalized area measure under an analytic self-mapping of $\mathbb D$. Nonetheless, we show that there exists a Carleson measure for the Bergman space such that its Berezin transform is bounded below but the corresponding Toeplitz operator is not invertible. On the Fock space, we show that $T_\mu$ is invertible if and only if $\mu$ is a reverse Carleson measure, but the invertibility of $T_\mu$ is not completely determined by the invertibility of the Berezin transform of $\mu$. These suggest that the answers to the Douglas question for Toeplitz operators induced by positive measures on the Bergman and Fock spaces are both negative in general cases., Comment: 17 pages

Fragile topology, akin to twisted bilayer graphene and the exotic phases therein, is a notable topological class with intriguing properties. However, due to its unique nature and the lack of bulk-edge correspondence, the experimental signature of fragile topology has been under debated since its birth. Here, we demonstrate experimentally that fragile topological phases with filling anomaly can be probed via screw dislocations, despite that they do not support gapless edge states. Using a designer hexagonal phononic crystal with a fragile topological band gap, we find that 1D gapless bound modes can emerge at a screw dislocation due to the bulk fragile topology. We then establish a connection between our system and the twisted boundary condition via the gauge invariance principle and illustrate that such an emergent phenomenon is an intrinsic property of fragile topological phases with filling anomaly. We observe experimentally the 1D topological bound states using the pump-probe measurements of their dispersion and wavefunctions, which unveils a novel bulk-defect correspondence of fragile topology and a powerful tool for probing fragile topological phases and materials., Comment: Submitted to Science Bulletin

The Silicon Charge Detector (SCD) is a subdetector of the High Energy Cosmic Radiation Detection payload. The dynamic range of the silicon microstrip detector can be extended by the capacitive coupling effect, which is related to the interstrip capacitance and the coupling capacitance. A detector prototype with several sets of parameters was designed and tested in the ion beams at the CERN Super Proton Synchrotron. The capacitive coupling fractions with readout strip and floating strip incidences were studied using the beam test data and SPICE simulation.

Non-Hermitian physics has greatly enriched our understanding of nonequilibrium phenomena and uncovered novel effects such as the non-Hermitian skin effect (NHSE) that has profoundly revolutionized the field. NHSE is typically predicted in systems with nonreciprocal couplings which, however, are difficult to realize in experiments. Without nonreciprocal couplings, the NHSE can also emerge in systems with coexisting gauge fields and loss or gain (e.g., in Floquet non-Hermitian systems). However, such Floquet NHSE remains largely unexplored in experiments. Here, we realize the Floquet NHSEs in periodically modulated optical waveguides integrated on a silicon photonics platform. By engineering the artificial gauge fields induced by the periodical modulation, we observe various Floquet NHSEs and unveil their rich topological transitions. Remarkably, we discover the transitions between the normal unipolar NHSEs and an unconventional bipolar NHSE which is accompanied by the directional reversal of the NHSEs. The underlying physics is revealed by the band winding in complex quasienergy space which undergoes a topology change from isolated loops with the same winding to linked loops with opposite windings. Our work unfolds a new route toward Floquet NHSEs originating from the interplay between gauge fields and dissipation effects and offers fundamentally new ways for steering light and other waves., Comment: 12 pages, 3 figures

Entanglement entropy is a fundamental concept with rising importance in different fields ranging from quantum information science, black holes to materials science. In complex materials and systems, entanglement entropy provides insight into the collective degrees of freedom that underlie the systems' complex behaviours. As well-known predictions, the entanglement entropy exhibits area laws for systems with gapped excitations, whereas it follows the Gioev-Klich-Widom scaling law in gapless fermion systems. Furthermore, the entanglement spectrum provides salient characterizations of topological phases and phase transitions beyond the conventional paradigms. However, many of these fundamental predictions have not yet been confirmed in experiments due to the difficulties in measuring entanglement entropy in physical systems. Here, we report the experimental verification of the above predictions by probing the nonlocal correlations in phononic systems. From the pump-probe responses in phononic crystals, we obtain the entanglement entropy and entanglement spectrum for phononic systems with the fermion filling analog. With these measurements, we verify the Gioev-Klich-Widom scaling law of entanglement entropy for various quasiparticle dispersions in one- and two-dimensions. Moreover, we observe the salient signatures of topological phases in the entanglement spectrum and entanglement entropy which unveil an unprecedented probe of topological phases without relying on the bulk-boundary correspondence. The progress here opens a frontier where entanglement entropy serves as an important experimental tool in the study of emergent phases and phase transitions which can be generalized to non-Hermitian and other unconventional regimes.

We investigate the detectability of gravitational waves that have been lensed by a spinless stellar-mass black hole, with respect to the advanced LIGO. By solving the full relativistic linear wave equations in the spacetime of a Schwarzschild black hole, we find that the strong gravity can create unique signals in the lensed waveform, particularly during the merger and ringdown stages. The differences in terms of fitting factor between the lensed waveform and best-fitted unlensed general relativity template with spin-precessing and higher-order multipoles are greater than $5\%$ for the lens black hole mass within $70M_{\odot}

Non-Hermitian effects have emerged as a new paradigm for the manipulation of phases of matter that profoundly changes our understanding of non-equilibrium systems, introducing novel concepts such as exceptional points and spectral topology, as well as exotic phenomena such as non-Hermitian skin effects (NHSEs). Most existing studies, however, focus on non-Hermitian eigenstates, whereas dynamic properties of non-Hermitian systems have been discussed only very recently, predicting unexpected phenomena such as wave self-healing, chiral Zener tunneling, and the dynamic NHSEs that are not yet confirmed in experiments. Here, we report the first experimental observation of rich non-Hermitian skin dynamics using tunable one-dimensional nonreciprocal double-chain mechanical systems with glide-time symmetry. Remarkably, dynamic NHSEs are observed with various dynamic behaviors in different dynamic phases, revealing the intriguing nature of these phases that can be understood via the generalized Brillouin zone and the related concepts. Moreover, the observed tunable non-Hermitian skin dynamics and amplifications, the bulk unidirectional wave propagation, and the boundary wave trapping provide promising ways to guide, trap, and amplify waves in a controllable and robust way. Our findings unveil the fundamental aspects and open a new pathway toward non-Hermitian dynamics, which will fertilize the study of non-equilibrium phases of matter and give rise to novel applications in information processing.

Quantum thermodynamics with microscopic inelastic scattering processes has been intensively investigated in recent years. Here, we apply quantum master equation combined with full counting statistics approach to investigate the role of quantum coherence on the periodically-driven inelastic heat engine. We demonstrate that the inelastic quantum heat engine exhibits dramatic advantage of thermodynamic performance compared to their elastic counterpart. Moreover, it is found that inelastic currents, {output work}, and the efficiency can be enhanced by quantum coherence. In particular, the geometric effect proves crucial in achieving maximal values of generated output work and energy conversion efficiency. The Berry curvature boosted by quantum coherence unveils the underlying mechanism of periodically-driven inelastic heat engine. Our findings may provide some insights for further understanding and optimizing periodically-driven heat engines via quantum coherence resource and inelastic scattering processes., Comment: 13 pages, 7 figures

Photonic crystals (PCs) are periodic dielectric structures that severed as an excellent platform to manipulate light. A conventional way to guide/trap light via PCs is to introduce a line or point defect by removing or modifying several unit cells. Here we show that the light can be effectively guided and trapped in the glided photonic crystal interfaces (GPCIs). The projected band gap of GPCIs, which depends on the glide parameter, is characterized by a Dirac mass. Interestingly, the GPCIs with zero Dirac mass is a glide-symmetric waveguide featured with excellent transmission performance even in the presence of sharp corners and disorders. Moreover, placing two GPCIs with opposite Dirac mass together results in a photonic bound state due to the Jackiw-Rebbi theory. Our work provides an alternative way towards the design of ultracompact photonic devices such as GPCIs-induced coupled cavity-waveguide system and waveguide splitter.

Diffusion driven by temperature or concentration gradients is a fundamental mechanism of energy and mass transport, which inherently differs from wave propagation in both physical foundations and application prospects. Compared with conventional schemes, metamaterials provide an unprecedented potential for governing diffusion processes, based on emerging theories like the transformation and the scattering cancellation theory, which enormously expanded the original concepts and suggest innovative metamaterial-based devices. We hereby use the term "diffusionics" to generalize these remarkable achievements in various energy (e.g., heat) and mass (e.g., particles and plasmas) diffusion systems. For clarity, we categorize the numerous studies appeared during the last decade by diffusion field (i.e., heat, particles, and plasmas) and discuss them from three different perspectives: the theoretical perspective, to detail how the transformation principle is applied to each diffusion field; the application perspective, to introduce various intriguing metamaterial-based devices, such as cloaks and radiative coolers; and the physics perspective, to connect with concepts of recent concern, such as non-Hermitian topology, nonreciprocal transport, and spatiotemporal modulation. We also discuss the possibility of controlling diffusion processes beyond metamaterials. Finally, we point out several future directions for diffusion metamaterial research, including the integration with artificial intelligence and topology concepts., Comment: This review article has been published in Reviews of Modern Physics, volume 96, 015002 (2024)

We first establish any continuum without interiors can be a limit set of iterations of an entire function on an oscillating wandering domain, and hence arise as a component of Julia sets. Recently, Luka Boc Thaler showed that every bounded connected regular open set, whose closure has a connected complement, is an oscillating or an escaping wandering domain of some entire function. A natural question is: What kind of domains can be realized as a periodic domain of some entire function? In this paper, we construct a sequence of entire functions whose invariant Fatou components can be approached to a regular domain.