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In this paper, an exact analytical solution is presented for achieving coherent population transfer and creating arbitrary coherent superposition states in a five-state chainwise system by a train of coincident pulses. We show that the solution of a five-state chainwise system can be reduced to an equivalent three-state Λ-type one with the simplest resonant coupling under the assumption of adiabatic elimination together with a requirement of the relation among the four coincident pulses. In this method, the four coincident pulses at each step all have the same time dependence, but with specific magnitudes. The results show that, by using a train of appropriately coincident pulses, this technique not only enables complete population transfer, but also creates any desired coherent superposition between the initial and final states, while the population in all intermediate states is effectively suppressed. Furthermore, this technique can also exhibit a one-way population transfer behavior. The results are of potential interest in applications where high-fidelity multi-state quantum control is essential, e.g., quantum information, atom optics, formation of ultracold molecules, cavity QED, nuclear coherent population transfer, and light transfer in waveguide arrays. [ABSTRACT FROM AUTHOR]

An accurate description of the long-range (LR) interaction is essential for understanding the collision between cold or ultracold molecules. However, to our best knowledge, there lacks a general approach to construct the intermolecular potential energy surface (IPES) between two arbitrary molecules and/or atoms in the LR region. In this work, we derived analytical expressions of the LR interaction energy, using the multipole expansion of the electrostatic interaction Hamiltonian and the non-degenerate perturbation theory. To make these formulae practical, we also derived the independent Cartesian components of the electrostatic properties, including the multipole moments and polarizabilities, of the monomer for a given symmetry using the properties of these components and the group-theoretical methods. Based on these newly derived formulae, we developed a FORTRAN program, namely ABLRI, which is capable of calculating the interaction energy between two arbitrary monomers both in their non-degenerate electronic ground states at large separations. To test the reliability of this newly developed program, we constructed IPESs for the electronic ground state of H2O–H2 and O2–H systems in the LR region. The interaction energy computed by our program agreed well with the ab initio calculation, which shows the validity of this program. [ABSTRACT FROM AUTHOR]

Advances in atomic physics have led to the possibility of a coherent transformation between ultracold atoms and molecules including between completely bosonic condensates. Such transformations are enabled by the magneto-association of atoms at a Feshbach resonance which results in a passage through a quantum critical point. In this study, we show that the presence of generic interaction between the constituent atoms and molecules can fundamentally alter the nature of the critical point, change the yield of the reaction and the order of the consequent phase transition. We find that the correlations introduced by this interaction induce nontrivial many-body physics such as coherent oscillations between atoms and molecules, and a selective formation of squeezed molecular quantum states and quantum cat states. We provide analytical and numerical descriptions of these effects, along with scaling laws for the reaction yield in non-adiabatic regimes. Experiments in the ultracold regime allow the possibility of associating fermionic/bosonic atoms into molecules by sweeping through a magnetic field. Here, the authors show that the presence and strength of interactions between the constituent atoms and molecules can create distinct and novel dynamical phases of matter. [ABSTRACT FROM AUTHOR]

Utilizing the anti-Zeno effect, we demonstrate that the resonances of ultracold molecular interactions can be selectively controlled by modulating the energy levels of molecules with a dynamic magnetic field. We show numerically that the inelastic scattering cross section of the selected isotopic molecules in the mixed isotopic molecular gas can be boosted for 2–3 orders of magnitude by modulation of Zeeman splittings. The mechanism of the resonant anti-Zeno effect in the ultracold scattering is based on matching the spectral modulation function of the magnetic field with the Floquet-engineered resonance of the molecular collision. The resulting insight provides a recipe to implement resonant anti-Zeno effect in control of molecular interactions, such as the selection of reaction channels between molecules involving shape and Feshbach resonances, and external field-assisted separation of isotopes. [ABSTRACT FROM AUTHOR]

We consider the calculations of photoionization spectra and core resonances of open-shell systems using range-separated time-dependent density-functional theory. Specifically, we use the time-dependent range-separated hybrid (TDRSH) scheme, combining a long-range Hartree–Fock exchange potential and kernel with a short-range potential and kernel from a local density-functional approximation, and the time-dependent locally range-separated hybrid (TDLRSH) scheme, which uses a local range-separation parameter. To efficiently perform the calculations, we formulate a spin-unrestricted linear-response Sternheimer approach in a non-orthogonal B-spline basis set using appropriate frequency-dependent boundary conditions. We illustrate this approach on the Li atom, which suggests that TDRSH and TDLRSH are adequate simple methods for estimating the single-electron photoionization spectra of open-shell systems. [ABSTRACT FROM AUTHOR]

While the rigorous time-independent close-coupling approach is ideally suited for cold and ultracold rovibrationally inelastic collision, its application beyond atom–diatom systems in full dimensionality is numerically expensive. Coupled-states (CS) approximation and its extensions are good choices to reduce the computational cost and have been successfully applied to diatom–diatom systems. In this work, we introduce the extended CS (ECS) approximation, in which one or a few nearest Coriolis coupled helicity channels are included. Its usefulness in atom–triatom systems is demonstrated for scattering of H2O with rare gas atoms. The results show that the ECS approximation, even when only the nearest neighbors are included, is generally much better than the CS approximation in describing scattering. At low collision energies, the ECS gradually converges to the exact results with the increasing number of Coriolis coupled helicity blocks. We further discuss three major factors that may lead to the failure of the CS approximation, namely, the reduced mass, collision energy, and triatomic rotational quantum number. It is illustrated that these factors could impact the relative importance of off-diagonal matrix elements in the Hamiltonian, thus influencing the coupling between different helicity channels. [ABSTRACT FROM AUTHOR]

In recent years, organic–inorganic hybrid perovskite materials have garnered extensive attention from scholars. Given its high absorption coefficient, carrier mobility, and diffusion length, it is widely studied for applications in various optoelectronic devices, such as solar cells, photodetectors, field-effect transistors, and light emitting diodes. Among them, the interfacial charge transfer process is a key factor influencing the performance of devices using perovskite materials. The charge transfer (CT) at the interface is typically detected via Raman spectroscopy. There are three types of related CT processes, namely, the interfacial ground state charge transfer, the photoinduced charge transfer resonance, and the electronic excitation resonance within the molecule itself. Among these factors, electronic excitation resonance manifests as an exciton resonance within the perovskite structure, providing energy for nearby charge transfer, thereby promoting charge transfer and enhancing Raman signals. Therefore, enhancing exciton resonance within the perovskite structure plays a crucial role in optoelectronic devices. This paper aimed to study the mechanism of oxygen plasma passivation of interstitial iodine defects and its enhancement effect on the Raman of perovskite substrates. Typically, interstitial iodine defects induce electron–hole recombination. In the process of oxygen plasma treatment, interstitial iodine is converted into pentavalent iodine, which can effectively fill related defects, inhibit electron–hole recombination, and prolong exciton lifetime, thereby promoting charge transfer and enhancing Raman intensity. [ABSTRACT FROM AUTHOR]

Unfair nature of doping practises adopted by dishonest sportsmen to increase their performance is posing a challenge to sports administrators worldwide. This involves giving them blood transfusions, using anabolic steroids, or even taking hormone-based medications like erythropoietin to improve their performance by increasing their strength, stamina, and endurance. Even while erythropoietin may be directly detected and identified in athlete blood samples, not all doping instances are easily identifiable, and certain tests are too expensive to perform on every sample. This makes it necessary to create an indirect technique based on many blood biomarkers to identify erythropoietin in blood samples. This study suggests a unique method for detecting steroids in athletes by combining machine learning models with quantum computing-based photon analysis. The information is gathered through medical examinations of athletes, after which photonic analysis is performed and the blood samples are categorised for steroid detection. Regressive Gaussian neural networks based on active equalisation are used to analyse the blood sample. The accuracy, mean average precision, F-1 score, positive predictive value, and mean average precision are all measured throughout the experimental study. The most significant injury risk variables may be found and players at high injury risk can be identified using current machine learning techniques. The proposed technique accuracy 97%, mean average precision 93%, positive predictive value 83%, F-1 score 89%. [ABSTRACT FROM AUTHOR]

We explore the merits of linear-response range-separated time-dependent density-functional theory (TDDFT) for the calculation of photoionization spectra. We consider two variants of range-separated TDDFT, namely, the time-dependent range-separated hybrid (TDRSH) scheme, which uses a global range-separation parameter, and the time-dependent locally range-separated hybrid (TDLRSH), which uses a local range-separation parameter, and compare with standard time-dependent local-density approximation (TDLDA) and time-dependent Hartree–Fock (TDHF). We show how to calculate photoionization spectra with these methods using the Sternheimer approach formulated in a non-orthogonal B-spline basis set with appropriate frequency-dependent boundary conditions. We illustrate these methods on the photoionization spectrum of the Be atom, focusing, in particular, on the core resonances. Both the TDRSH and TDLRSH photoionization spectra are found to constitute a large improvement over the TDLDA photoionization spectrum and a more modest improvement over the TDHF photoionization spectrum. [ABSTRACT FROM AUTHOR]

Systematic quantum chemical calculations were performed for the ground and a number of low-lying electronically excited doublet and quartet states of the rubidium trimer molecule. The obtained potential energy surfaces (PES), spin-orbit couplings (SOC) and electronic transition dipole moments (ETDM) can be useful for optimizing paths for laser synthesis, cooling and manipulation of stable ensembles of Rb3 molecules at ultralow temperatures. Ab initio calculations of the electronic structure of the homonuclear Rb3 molecule, in linear, isosceles triangle and equilateral triangle geometries, were performed using the multi-reference configuration interaction method, taking into account single and double excitations (M-R‑CISD) and with explicit dynamic correlation of only the three valence electrons. The structure of each atom was approximated using a nine-electron effective core potential (ECP28MDF), and molecular orbitals (MOs) were optimized using the spin averaged (over doublet and quartet states) multi-configuration self-consistent field (SA-CASSCF) method. Core–valence correlations between twenty-four subvalence electrons located on doubly occupied MOs and three valence electrons were implicitly taken into account using a one-electron angular momentum-independent Müller–Mayer core polarization potential (CPP). As a result of topological investigations at over 35 000 points, two dimensional PES, SOC, and ETDM functions were obtained and the geometric parameters Rb3 were found at which the most intense vertical transitions and the maximum influence of the SOC are expected. [ABSTRACT FROM AUTHOR]

SmI2 is a versatile reagent in single electron transfer‐mediated reductive transformations. Photoexcitation of SmI2 generates a reactive excited state capable of transferring an electron to substrates that are recalcitrant towards accepting electrons. Synthetic results unequivocally indicate light as a green and sustainable promoter of SmI2‐mediated chemistry, with the potential to replace the suspected carcinogen hexamethylphosphoramide (HMPA). Rate constants of photoinduced electron transfer from SmI2 are in the range of 107–109 M−1 s−1, which are an order of magnitude higher in comparison with the ground state process. Recent advancement in EuII‐ and CeIII‐based photo‐redox catalysis rejuvenated the area of photo‐catalyzed reactions of low‐valent lanthanides. This review article aims to illustrate the role of photoexcitation on SmI2‐mediated reductive transformations. [ABSTRACT FROM AUTHOR]

In past years, optical lattices have been demonstrated as an excellent platform for making, understanding, and controlling quantum matters at nonlinear and fundamental quantum levels. Shrinking experimental observations include matter-wave gap solitons created in ultracold quantum degenerate gases, such as Bose–Einstein condensates with repulsive interaction. In this paper, we theoretically and numerically study the formation of one-dimensional gap soliton molecules and clusters in ultracold coherent atom ensembles under electromagnetically induced transparency conditions and trapped by an optical lattice. In numerics, both linear stability analysis and direct perturbed simulations are combined to identify the stability and instability of the localized gap modes, stressing the wide stability region within the first finite gap. The results predicted here may be confirmed in ultracold atom experiments, providing detailed insight into the higher-order localized gap modes of ultracold bosonic atoms under the quantum coherent effect called electromagnetically induced transparency. [ABSTRACT FROM AUTHOR]

Ultracold polar molecules are promising candidate qubits for quantum computing and quantum simulations. Their long-lived molecular rotational states form robust qubits, and the long-range dipolar interaction between molecules provides quantum entanglement. In this work, we demonstrate dipolar spin-exchange interactions between single calcium monofluoride (CaF) molecules trapped in an optical tweezer array. We realized the spin-1/2 quantum XY model by encoding an effective spin-1/2 system into the rotational states of the molecules and used it to generate a Bell state through an iSWAP operation. Conditioned on the verified existence of molecules in both tweezers at the end of the measurement, we obtained a Bell state fidelity of 0.89(6). Using interleaved tweezer arrays, we demonstrate single-site molecular addressability. [ABSTRACT FROM AUTHOR]

Lipid oxidation by reactive oxygen species (ROS) provide several different oxidation products that have been implicated in inflammatory responses. Ground state atomic oxygen [O(3P)] is produced by the photodeoxygenation of certain heterocyclic oxides and has a reactivity that is unique from other ROS. Due to the reactive nature of O(3P), the site of O(3P)‐generation is expected to influence the products in heterogenous solutions or environments. In this work, the oxidation of low‐density lipoprotein (LDL) by lipids with covalently bound O(3P)‐photoprecursors was compared to more hydrophilic O(3P)‐photoprecursors. Lipid oxidation products were quantified after Bligh‐Dyer extraction and pentafluorobenzyl bromide (PFB) derivatization by GC–MS. Unlike the more hydrophilic O(3P)‐photoprecursors, the oxidation of LDL during the irradiation of lipid‐(O3P)‐photoprecursor conjugates showed little quenching by the addition of the O(3P)‐scavenging sodium allyl sulfonate. This indicated that lipophilic O(3P)‐photoprecursors are expected to generate lipid oxidation products where other more hydrophilic O(3P)‐photoprecursors could be quenched by other reactive groups present in solution or the environment. [ABSTRACT FROM AUTHOR]

The recent disclosure of the ability of aromatic isocyanides to harvest visible light and act as single electron acceptors when reacting with tertiary aromatic amines has triggered a renewed interest in their application to the development of green photoredox catalytic methodologies. Accordingly, the present work explores their ability to promote the generation of both alkyl and acyl radicals starting from radical precursors such as Hantzsch esters, potassium alkyltrifluoroborates, and α‐oxoacids. Mechanistic studies involving UV‐visible absorption and fluorescence experiments, electrochemical measurements of the ground‐state redox potentials along with computational calculations of both the ground‐ and the excited‐state redox potentials of a set of nine different aromatic isocyanides provide key insights to promote a rationale design of a new generation of isocyanide‐based organic photoredox catalysts. Importantly, the green potential of the investigated chemistry is demonstrated by a direct and easy access to deuterium labeled compounds. [ABSTRACT FROM AUTHOR]

The scattering- and bound-state properties of two 133Cs atoms, in free space as well as in low-dense Cs vapor, are calculated for both electronic singlet and triplet states. In free space, standard scattering theory is used; specifically, the Lippmann–Schwinger t-matrix equation is solved by a matrix-inversion technique. The output is the phase shifts, from which the corresponding (total, viscosity, [complex] spin-exchange, and average) cross sections are computed. In the vapor, a generalized scattering theory is invoked, the key equation being the Galitskii–Migdal–Feynman T-matrix equation. This is solved by the same technique to obtain the cross sections in the medium. Likewise, the t- and T-matrix equations are solved for negative definite energy eigenvalues—again, by matrix inversion, albeit after symmetrizing the kernel in the integral equation involved—to determine the respective binding energies of the Cs2 dimer in free space and in the vapor. Sharp resonance peaks, representing 'quasi' bound states, appear in the cross sections. In the triplet total and viscosity cross sections, quantum effects appear as undulations. The results obtained for the complex spin-exchange cross sections are particularly highlighted, because of their importance in the spectroscopy of the 133Cs2 dimer. So are the results for the binding energy of this dimer, which are important in the physics of ultracold molecules. In calculating this quantity, as many relative partial waves as necessary (ℓ = 0–7 and 0–8 in free space and the medium, respectively) are taken into account to guarantee 'convergence'. The role of the medium is given special attention throughout. Most of the quantities considered here are calculated for the first time; but whenever available, comparison is made with previous results. [ABSTRACT FROM AUTHOR]

Cryogenic buffer gas beams are central to many cold molecule experiments. Here, we use absorption and fluorescence spectroscopy to directly compare molecular beams of AlF, CaF, MgF and YbF molecules, produced by chemical reaction of laser ablated atoms with fluorine rich reagents. The beam brightness for AlF is measured as 2 × 10 12 molecules per steradian per pulse in a single rotational state, comparable to an Al atomic beam produced in the same setup. The CaF, MgF and YbF beams show an order of magnitude lower brightness than AlF and far below the brightness of Ca and Yb beams. The addition of either NF 3 or SF 6 to the cell extinguishes the Al atomic beam, but has a minimal effect on the Ca and Yb beams. NF 3 reacts more efficiently than SF 6 , as a significantly lower flow rate is required to maximise the molecule production, which is particularly beneficial for long-term stability of the AlF beam. We use NO as a proxy for the reactant gas as it can be optically detected. We demonstrate that a cold, rotationally pure NO beam can be generated by laser desorption, thereby gaining insight into the dynamics of the reactant gas inside the buffer gas cell. [ABSTRACT FROM AUTHOR]

The photochemical properties and straightforward synthesis of a wide range of azo dyes has led to their use in a wide range of applications. Despite their broad use, the fundamental structure-function relationships of many variants are unexplored. Here, azo dyes with a pyridine moiety are systematically investigated. The pyridine affords a range of electronic effects due to the position of the nitrogen heteroatom relative to the azo bond and serves as a second protonatable site that provides a way to alter the isomerization yield of the dye through inductive effects and protonation. Photometric titrations, visible-light photoisomerization, and density functional theory (DFT) calculations reveal and rationalize the unexpected loss of photoisomerization that occurs upon protonation of the pyridine N (the first protonation site on the pyridine-based azo dyes). The result is particularly surprising as this site is not adjacent to or on the azo bond and yet it completely shuts downs bulk photoisomerization. The first protonation of the azo dyes onto the pyridine N results in a red shift of the spectra by 132 nm, 64 nm and 106 nm for Pyr2, Pyr3, and Pyr4, respectively. The second protonation onto the azo bond blueshifts the spectra by 102 nm, 19 nm, and 89 nm, respectively. pKa values of the pyridine N are 14.9, 14.6 and 15.3, while the pKa values of the azo bond N are 11.3, 11.4, and 13.8, for Pyr2, Pyr3, and Pyr4, respectively. DFT reveals that the loss of photoisomerization arises from both a reduction in the generated cis-isomer upon photoexcitation and an accelerated cis to trans reversion process on the ground-state potential energy surface. [ABSTRACT FROM AUTHOR]

Feshbach association of ultracold molecules using narrow resonances requires exquisite control of the applied magnetic field. Here, we present a magnetic field control system to deliver magnetic fields of over 1000 G with ppm-level precision integrated into an ultracold-atom experimental setup. We combine a battery-powered, current-stabilized power supply with active feedback stabilization of the magnetic field using fluxgate magnetic field sensors. As a real-world test, we perform microwave spectroscopy of ultracold Rb atoms and demonstrate an upper limit on our magnetic field stability of 2.4(3) mG at 1050 G [2.3(3) ppm relative] as determined from the spectral feature. [ABSTRACT FROM AUTHOR]

A diversity of experimental techniques has been developed over the last 25 years to create samples of molecular gases at temperatures close to the Absolute Zero—here we consider samples in the range from 10s of Kelvin (cold) down to 10s of nanoKelvin (ultracold). In these exotic physical environments, a range of novel experiments can be conducted which bring high levels of control over the properties of these 'almost stationary' molecules, in some cases with control over single trapped molecules achievable. In this article, recent advances in this field since 2020, both in terms of the ability to produce and manipulate the molecules and understand their properties, and also in the development of new applications of these technologies, are highlighted. Applications include observing explicit 'quantum effects' in chemical reactivity, developing an understanding of chemistry in cold astrophysical media, the creation of exotic phases of matter, the use of trapped molecules in quantum computation and simulations systems, and the use of very high-precision spectroscopic measurements to answer fundamental physics questions beyond the standard model of particle physics. [ABSTRACT FROM AUTHOR]

We explore the rich nature of correlations in the ground state of ultracold atoms trapped in state-dependent optical lattices. In particular, we consider interacting fermionic ytterbium or strontium atoms, realizing a two-orbital Hubbard model with two spin components. We analyze the model in one-dimensional setting with the experimentally relevant hierarchy of tunneling and interaction amplitudes by means of exact diagonalization and matrix product states approaches, and study the correlation functions in density, spin, and orbital sectors as functions of variable densities of atoms in the ground and metastable excited states. We show that in certain ranges of densities these atomic systems demonstrate strong density-wave, ferro- and antiferromagnetic, as well as antiferroorbital correlations. [ABSTRACT FROM AUTHOR]

In chaotic many-body systems, scrambling or the operator growth can be diagnosed by out-of-time-order correlators of local operators. We show that operator growth also has a sharp imprint in out-of-time-order correlators of global operators. In particular, the characteristic spacetime shape of growing local operators can be accessed using global measurements without any local control or readout. Building on an earlier conjectured phase diagram for operator growth in chaotic systems with power-law interactions, we show that existing nuclear spin data for out-of-time-order correlators of global operators are well fit by our theory. We also predict super-polynomial operator growth in dipolar systems in 3d and discuss the potential observation of this physics in future experiments with nuclear spins and ultra-cold polar molecules. Out-of-time-ordered correlators of local operators can quantify information scrambling in quantum many-body systems, but they are not easily accessible in experiments. Here the authors show that their global versions can be used for the same purpose and has been measured in nuclear magnetic resonance experiments. [ABSTRACT FROM AUTHOR]

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This paper introduces a quasi-resonant high-efficiency high-step-up DC–DC converter requiring a reduced number of components. The proposed circuit uses a coupled inductor associated with voltage multiplier cells to ensure high-voltage-gain operation without the necessity of an extremely high number of turns ratio. Quasi-resonant operation guarantees zero current switching (ZCS) for some diodes of the converter. A detailed steady-state analysis is carried out aiming at the adequate design of the circuit. Experimental results taken from the testing of a 400 W prototype operating in closed loop with an input voltage range of 25–48 V, output voltage of 400 V and switching frequency of 100 kHz validate the analysis carried out and demonstrate the feasibility of the proposed converter. [ABSTRACT FROM AUTHOR]

A cold collision between atoms and molecules (<1 K) is one of the hot research fields in atomic and molecular physics. At low temperatures, the number of partial waves participating in the collision process decreases dramatically, and quantum phenomena start to emerge. The reaction is often dominated by quantum tunneling, and pronounced resonances can exist on collision cross sections. Here, we report on an apparatus designed for studying cold collisions between metastable noble gas atoms and alkali atoms. Our apparatus features a combined Magneto-Optical-Trap (MOT) and velocity map imaging (VMI) system. The center of a Rb MOT is overlapped with the VMI system. Cold Kr* atoms are launched toward the Rb atoms to induce Kr* + Rb reactions. The collision energy between the two species can be varied from 100 mK to 20 K. With this setup, we are planning to explore the quantum phenomena in Kr* + Rb cold collisions, including the shape resonance and stereodynamics in the reaction. [ABSTRACT FROM AUTHOR]

Theoretical schemes for the implementation of the Grover search algorithm are proposed based on ultracold polar molecules in an electric field. The molecular qubits and qudit are chosen as the field‐dressed states formed by the rotational modes of CH3CN. With the help of multi‐target optimal control theory, the microwave pulses for the elementary logic operations including the one‐qubit Hadamard gates and the conditional phase gates in a dipole‐dipole system are designed and the factorized Grover algorithm demonstrated using two coupled CH3CN molecules. To reduce the accumulation of imprecision and decoherence resulting from the combination of multiple elementary gates, the optimal pulses that can achieve the two‐qubit Hadamard gate and diffusion operation in one step are designed successfully. In this way, the probabilities to find the states corresponding to the desired elements in an unsorted database are enhanced to some extent. Moreover, the optimal pulse sequence suitable for a four‐level molecular qudit, which can be used to simulate the quantum search on a single CH3CN molecule with high fidelity, is designed. These results can shed some light on the physical realization of quantum computing based on ultracold polyatomic molecules. [ABSTRACT FROM AUTHOR]

In this article, effects of the strong long-range interaction of Rydberg atoms on the Autler–Townes splitting spectrum are investigated. Preliminary results are obtained for various excitation times and Rydberg atom densities. The 2 S 1 / 2 and 2 P 1 / 2 levels of lithium-7 are coupled with strong laser field and probed by another laser via excitation into a 70 S Rydberg level. Interactions between Rydberg atoms excited by the probe beam lead to the broadening of the Autler–Townes spectra. At high concentrations of Rydberg atoms, a suppression of the excitation of the Autler–Townes peak at red detuning is observed. [ABSTRACT FROM AUTHOR]

Molecules have vibrational, rotational, spin-orbit and hyperfine degrees of freedom or quantum states, each of which responds in a unique fashion to external electromagnetic radiation. The control over superpositions of these quantum states is key to coherent manipulation of molecules. For example, the better the coherence time the longer quantum simulations can last. The important quantity for controlling an ultracold molecule with laser light is its complex-valued molecular dynamic polarizability. Its real part determines the tweezer or trapping potential as felt by the molecule, while its imaginary part limits the coherence time. Here, our study shows that efficient trapping of a molecule in its vibrational ground state can be achieved by selecting a laser frequency with a detuning on the order of tens of GHz relative to an electric-dipole-forbidden molecular transition. Close proximity to this nearly forbidden transition allows to create a sufficiently deep trapping potential for multiple rotational states without sacrificing coherence times among these states from Raman and Rayleigh scattering. In fact, we demonstrate that magic trapping conditions for multiple rotational states of the ultracold ^23 Na ^87 Rb polar molecule can be created.

Quantum computing promises exponential speed-up compared to its classical counterpart. While the neutral atom processors are the pioneering platform in terms of scalability, the dipolar Rydberg gates impose the main bottlenecks on the scaling of these devices. This article presents an alternative scheme for neutral atom quantum processing, based on the Fermi scattering of a Rydberg electron from ground-state atoms in spin-dependent lattice geometries. Instead of relying on Rydberg pair-potentials, the interaction is controlled by engineering the electron cloud of a sole Rydberg atom. The present scheme addresses the scaling obstacles in Rydberg processors by exponentially suppressing the population of short-lived states and by operating in ultra-dense atomic lattices. The restoring forces in molecule type Rydberg-Fermi potential preserve the trapping over a long interaction period. Furthermore, the proposed scheme mitigates different competing infidelity criteria, eliminates unwanted cross-talks, and significantly suppresses the operation depth in running complicated quantum algorithms. Current Rydberg quantum processors suffer from limitations in fidelity and scalability. Here, the authors address these limitations by proposing highly controllable multi-qubit operations that utilize the Fermi scattering of Rydberg electrons trapped in an optical lattice. [ABSTRACT FROM AUTHOR]

We study the critical behavior of a mixture of two species of lattice bosons described by the extended Bose–Hubbard model. Our goal is to analyze in which conditions exotic orderings like pair superfluid or counterflow superfluid could be detected. We use a numerical method based on mean field approximation to calculate the phase diagram of the system, along with particle density, and order parameter profiles in selected multicritical points. We observe that the phase diagram becomes significantly renormalized in the presence of pair flow or counterflow. Furthermore, a critical particle density emerges, which isolates a new region of the phase diagram, in which the exotic order parameter exists for any value of single-particle hopping. [ABSTRACT FROM AUTHOR]

We theoretically investigate the optical response and the propagation of an external probe field in a Fabry–Perot cavity, which consists of a mechanical mode of trapped, ultracold, fermionic atoms inside and simultaneously driven by an optical laser field. We investigate the electromagnetically-induced transparency due to coupling of the optical cavity field with the collective density excitations of the ultracold fermionic atoms via radiation pressure force. Moreover, we discuss the variations in the phase and group delay of the transmitted probe field with respect to effective cavity detuning as well as pumping power. It is observed that the transmitted field is lagging in this fermionic cavity optomechanical system. Our study shall provide a method to control the propagation as well as the speed of the transmitted probe field in this kind of fermionic, ultracold, atom-based, optomechanical cavity system, which might have potential applications in optical communications, signal processing and quantum information processing. [ABSTRACT FROM AUTHOR]

The use of atom interferometers in inertial systems holds the promise of improvement of several orders of magnitude in sensitivity over sensors using current technology such as micro-electro-mechanical (MEMS) devices or ring laser gyroscopes (RLGs). This paper describes the construction and characterization of an atomic interferometry system for eventual use in a dual-atom-beam accelerometer/gyroscope sensor. In contrast with current state-of-the-art atomic sensors which use pulsed cold atom sources and pulsed laser beams, the investigated apparatus relies purely on continuous atomic and laser beams. These differences can result in a sensor with reduced complexity, a smaller physical footprint, and reduced power consumption. However, these differences also introduce challenges resulting from laser and atomic beam divergences and from velocity averaging due to both longitudinal and transverse velocity spreads. In this work, we characterize our rubidium-based atom beam system and show that Ramsey-style interference can still be observed. The implications for future research are also outlined and discussed. [ABSTRACT FROM AUTHOR]

We consider a condensate of ultra-cold bosonic atoms in a linear optical cavity illuminated by a two-pump configuration where each pump makes different angles with the direction of the cavity axis. We show that such a configuration allows a smooth transition from a one-dimensional quantum optical lattice configuration to a two-dimensional quantum optical lattice configuration induced by the cavity–atom interaction. Using a Holstein–Primakoff transformation, we find the atomic density profile of such a self-organised ground state in the super-radiant phase as a function of the angular orientations of the pumps in such a dynamical quantum optical lattice, and also provide an analysis of their structures in coordinate and momentum space. In the later part of the paper, we show how the corresponding results can also be qualitatively understood in terms of an extended Bose–Hubbard model in such a quantum optical lattice potential. [ABSTRACT FROM AUTHOR]

The interplay of the staggered and the three‐body interaction potentials on the quantum phases of a spin‐1 Bose Hubbard model using a mean field approximation (MFA) is studied. In the antiferromagnetic (AF) case, a smaller value of the staggered potential (SP) results in the charge and the spin density wave ordering along with the Mott insulator (MI) and the staggered superfluid (SSF) phases. While the competition between two types of the potential leads to the stabilization of the higher order MI and charge density wave (CDW) phases with increasing three‐body interaction strength. Further, the spin eigenvalue and nematic order parameters are calculated to scrutinize the spin singlet‐nematic formation in the MI and the CDW phases and spin population fractions to analyze the nature of the SSF phase. A signature of the spin density wave (SDW) pattern is also observed in the gapped phase lobes. In case of a purely three‐body interaction, the third and higher order insulating lobes become dominant with increasing staggered potential strength. Subsequently, all MFA phase diagrams are then nicely corroborated with the analytical results obtained using a perturbative expansion corresponding to the AF and ferromagnetic cases. [ABSTRACT FROM AUTHOR]

Herein we report the results of multi-element nitride and intermetallic coatings obtained by the arc-PVD method based on non-trivial elements combinations (Nb - 75.5, Si - 9.65, Cu - 14.85 at% and Ti - 81.8, Nb - 11.8, Al - 6.4 at%). Our experiments examine the development and evolution of biocompatible coatings for metal implants and medical devices. The elemental composition of the surface, microstructure, contact angle and biocompatibility of the coatings were studied. XRD results demonstrated that in the intermetallic TiAlNb samples, a multiphase state is formed between γ-TiAl, TiAl 2 , and α-Nb 5 Si 3 , since only a small part of Nb atoms occupy the same lattice sites as Ti atoms, which leads to the formation of a competing phase α-Nb 5 Si 3. The NbCuSi coatings predominantly consist of Nb ss with inclusions of silicon silicide. The human umbilical cord mesenchymal stem cells (MSC) were used for biocompatibility assessment using resazurin reduction assay and fluorescent DAPI staining. We show the high biocompatibility and ability to stimulate cell proliferation and distribution over the intermetallic coatings, especially when compared to nitrides ones. Although intermetallic coatings exhibit a higher surface contact angle due to uneven morphology, all samples exhibit hydrophilic properties, which favourably affect cell adhesion and proliferation. [ABSTRACT FROM AUTHOR]

It is known that effects of dissipation or measurement backreaction in postselected quantum trajectories are described by a non-Hermitian Hamiltonian, but their consequences in real-time dynamics of many-body systems are yet to be elucidated. Through a study of a non-Hermitian Hubbard model, we reveal a novel dissipation-induced dynamical phase transition in postselected quantum trajectories, where time controls the strength of postselection and becomes the intrinsic parameter inducing the phase transition. Our findings are testable in ultracold atom experiments and may open a new avenue in the dissipative engineering of quantum systems. [ABSTRACT FROM AUTHOR]

Mg2SiO4:Eu2+ phosphors with olivine structure were prepared by the solid-state reaction under a reducing atmosphere, and their phase composition, crystal structure, microscopic morphology, and photoluminescence properties were investigated. It was suggested that Eu2+ ions occupied the lattice of Mg2+ ions, and a small amount of Eu2+ ions doping (0.05% ~ 0.2%) did not affect the crystal structure and morphology of the Mg2SiO4. The samples were crystallized into ellipsoidal particles with a size of 1–3 μm. The optimal doping concentration of Eu2+ ions in Mg2-xSiO4: xEu2+ phosphors is 0.1%. Upon the excitation of 275 nm ultraviolet light, the Mg2-xSiO4: xEu2+(x = 0.1%) sample exhibited a broad emission band with the maximum emission intensity at 453 nm, which is in the spectral absorption range of chlorophyll A and chlorophyll B, thus enabling the enhancement of the photosynthesis of the plant growth. The emission spectrum of the sample is decomposed into two subbands by the Gaussian method, which corresponds to the 5d-4f transitions of Eu2+ ions occupying the Mg1 and Mg2 lattice sites, respectively. In addition, the fluorescence decay behavior and thermal stability of the Mg2-xSiO4: xEu2+(x = 0.1%) sample were analyzed, and the sample showed good thermal stability. These results indicate that the Mg2SiO4:Eu2+ phosphor has enormous potential in plant lighting. [ABSTRACT FROM AUTHOR]

In this study, we investigated PFAS (per- and polyfluoroalkyl substances) binding potencies to nuclear hormone receptors (NHRs): peroxisome proliferator-activated receptors (PPARs) α, β, and γ and thyroid hormone receptors (TRs) α and β. We have simulated the docking scores of 43 perfluoroalkyl compounds and based on these data developed QSAR (Quantitative Structure-Activity Relationship) models for predicting the binding probability to five receptors. In the next step, we implemented the developed QSAR models for the screening approach of a large group of compounds (4464) from the NORMAN Database. The in silico analyses indicated that the probability of PFAS binding to the receptors depends on the chain length, the number of fluorine atoms, and the number of branches in the molecule. According to the findings, the considered PFAS group bind to the PPARα, β, and γ only with low or moderate probability, while in the case of TR α and β it is similar except that those chemicals with longer chains show a moderately high probability of binding. [ABSTRACT FROM AUTHOR]

The exploration of non‐noble metal electrocatalysts with high catalytic activity and stability for oxygen evolution reaction (OER) has become particularly urgent. Here, FeNi‐based Prussian blue analogues (PBAs) were obtained by adding different solvents, where PBA particles preferentially grew on the surface plane/edge of coordination polymer precursor (Ni‐ABDC) with various polarities. This resulted in the formation of FeNi‐PBA‐plane/edge morphologies, respectively. Notably, on account of more exposed PBAs, FeNi nanoparticles were uniformly supported on the porous N‐doped carbon nanomaterials. Among them, the calcined FeNi‐NC‐800 underwent an interesting pre‐activation process and exhibited a low overpotential of 281 mV at 10 mA cm−2 and a small Tafel slope of 82 mV dec−1 in 1.0 m KOH. This bimetallic sample showed superior OER activity and stability in comparison with control materials, which could be attributed to its abundant FeNi nanoparticles, high nitrogen content, large specific surface area, and synergistic effects between Fe and Ni atoms. In addition, relevant theoretical calculation on the optimal catalyst, FeNi‐NC‐800, further demonstrated its efficient OER performance with effective Fe‐doping in the Ni‐based oxyhydroxides. [ABSTRACT FROM AUTHOR]

The search for fundamental determinants of bio-molecular chirality is a hot topic in biology, clarifying the meaning of evolution and the enigma of life's origin. The question of origin may be resolved assuming that non-biological and biological entities obey nature's universal laws grounded on space-time symmetry (STS) and space-time relativity (SPR). The fabric of STS is our review's primary subject. This symmetry, encompassing the behavior of elementary particles and galaxy structure, imposes its fundamental laws on all hierarchical levels of the biological world. From the perspective of STS, objects across spatial scales may be classified as chiral or achiral concerning a specific space-related symmetry transformation: mirror reflection. The chiral object is not identical (i.e., not superimposable) to its mirror image. In geometry, distinguish two kinds of chiral objects. The first one does not have any reflective symmetry elements (a point or plane of symmetry) but may have rotational symmetry axes (dissymmetry). The second one does not have any symmetry elements (asymmetry). As the form symmetry deficiency, Chirality is the critical structural feature of natural systems, including sub-atomic particles and living matter. According to the Standard Model (SM) theory and String Theory (StrT), elementary particles associated with the four fundamental forces of nature determine the existence of micro- and galaxy scales of nature. Therefore, the inheritance of molecular symmetry from the symmetry of elementary particles indicates a bi-directional (internal [(micro-scale) and external (galaxy sale)] causal pathway of prevalent bio-chirality. We assume that the laws of the physical world impact the biological matter's appearance through both extremities of spatial dimensions. The extended network of multi-disciplinary experimental evidence supports this hypothesis. However, many experimental results are derived and interpreted based on the narrow-view prerogative and highly specific terminology. The current review promotes a holistic approach to experimental results in two fast-developing, seemingly unrelated, divergent branches of STS and biological chirality. The generalized view on the origin of prevalent bio-molecular chirality is necessary for understanding the link between a diverse range of biological events. The chain of chirality transfer links ribosomal protein synthesis, cell morphology, and neuronal signaling with the laterality of cognitive functions. [ABSTRACT FROM AUTHOR]

To obtain reliable and scalable cells in 3D cross‐point memory, endurance failures caused by voiding from etching damage to memory cells should be resolved to preserve the properties of GeSbTe (GST) phase‐change materials. Herein, the fabrication of a damascene cell without patterning, which relies on the bottom‐up fill of carbon‐doped GST layers into confined cells, is proposed as a promising solution. The reflow fill of the sputtered carbon‐doped GST films into confined cells at high‐temperature and low‐power conditions is demonstrated, and a mechanism in which Sb and Te transfer into the cell through vapor transfer and viscous flow due to capillary pressure is verified. The aspect ratio increases from 2 to 7.7 under enhanced vaporization of Sb and Te as well as the capillary force. The advanced reflow‐fill process using a laser can overcome the limit of the conventional reflow‐fill technology by increasing the atomic mobility above the melting temperature. Based on the proposed method, 19 nm cross‐point memory devices are successfully integrated together with the Ovonyx threshold switch and appropriate memory windows are secured. Furthermore, the 9 nm cells exhibit reliable endurance cycles over 108. [ABSTRACT FROM AUTHOR]

The construction of high‐efficiency and low‐cost non‐noble metal bifunctional electrocatalysts for water electrolysis is crucial for commercial large‐scale application of hydrogen energy. Here, we report a novel strategy with erbium‐doped NiCoP nanowire arrays in situ grown on conductive nickel foam (Er‐NiCoP/NF). Significantly, the developed electrode shows exceptional bifunctional catalytic activity, which only requires overpotentials of 46 and 225 mV to afford a current density of 10 mA cm−2 for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Density functional theory calculations reveal that the appropriate Er incorporation into the NiCoP lattice can significantly modulate the electronic structure with the d‐band centers of Ni and Co atoms by shifting to lower energies with respect to the Fermi level, and optimize the Gibbs free energies of HER/OER intermediates, thereby accelerating water‐splitting kinetics. When assembled as a solar‐driven overall water‐splitting electrolyzer, the as‐prepared electrode shows a high and stable solar‐to‐hydrogen efficiency of 19.6%, indicating its potential for practical storage of intermittent energy. [ABSTRACT FROM AUTHOR]

Based on density functional theory, the ground state for ultracold Fermi gases with dipole–dipole interaction is a functional minimization problem with orthonormality constraints. Many methods such as direct minimization, self-consistent iteration method and first-order gradient flow had been proposed to solve such problem. In this paper, we introduce the second-order Sobolev gradient flows, solve them to the steady state and get the ground state of ultracold Fermi gases numerically. Two contributions have been made: firstly we extend the usual first-order gradient flows to the second-order gradient flows; secondly, we extend the usual L 2 gradient to the Sobolev gradient and get the Sobolev gradient flows. We prove that the second-order Sobolev gradient flows have the properties of orthonormality preserving and 'modified' energy diminishing, which are desirable for the computation of the ground state solution. Several numerical techniques have been used to discretize the time-dependent second-order Sobolev gradient flows. These include explicit leap-frog method and stabilized semi-implicit method for temporal discretization and Fourier pseudo-spectral method for spatial variables. Extensive numerical examples for the ground state are reported to demonstrate the power of the numerical methods. [ABSTRACT FROM AUTHOR]

The integration of bottom-up fabrication techniques and top-down methods can overcome current limits in nanofabrication. For such integration, we propose a gradient area-selective deposition using atomic layer deposition to overcome the inherent limitation of 3D nanofabrication and demonstrate the applicability of the proposed method toward large-scale production of materials. Cp(CH3)5Ti(OMe)3 is used as a molecular surface inhibitor to prevent the growth of TiO2 film in the next atomic layer deposition process. Cp(CH3)5Ti(OMe)3 adsorption was controlled gradually in a 3D nanoscale hole to achieve gradient TiO2 growth. This resulted in the formation of perfectly seamless TiO2 films with a high-aspect-ratio hole structure. The experimental results were consistent with theoretical calculations based on density functional theory, Monte Carlo simulation, and the Johnson-Mehl-Avrami-Kolmogorov model. Since the gradient area-selective deposition TiO2 film formation is based on the fundamentals of molecular chemical and physical behaviours, this approach can be applied to other material systems in atomic layer deposition. Integrating bottom-up and top-down fabrication techniques can overcome limits in nanofabrication. Here authors demonstrate an approach for area selective deposition using Ti as an inhibitor in the atomic layer deposition process to achieve controlled growth of seamless TiO2 layers on 3D structures. [ABSTRACT FROM AUTHOR]