Human behavioral decision-making influences the gaming environment. In turn, changes in the gaming environmental impact individual strategic choices. However, there is scant exploration into how human behavioral decision-making coevolves with dilemma strength. Here, we propose a coevolutionary game model based on collective-risk social dilemma, where an increase in cooperators within the game group reduces the dilemma strength, and vice versa. Upon examining this coupled system, we find that the system is capable of achieving a relatively optimal state, wherein the population sustains a high level of cooperation and the dilemma strength remains at the lowest level. In addition, we have identified the conditions for the emergence of tristability and bistability in the coupled system and numerically validated our theoretical results. Furthermore, we find that the incorporation of institutional rewards not only promotes the appearance of the system's optimal state, where all individuals choose to cooperate and the dilemma strength is at its lowest level, but it also effectively averts the manifestation of the system's worst state, where all individuals resort to defection and the dilemma strength reaches its highest level. These findings illuminate how cooperation can be sustained when a dynamical coupling exists between individual decision-making and dilemma strength.

Picosecond ultrasonics is a fast growing and advanced research field with broad application to the imaging and characterization of nanostructured materials as well as at a fundamental level. The aim of this paper is to provide an advanced 3D model based on atomistic spin-lattice simulations of the laser-induced elastic response in ferromagnetically ordered fcc Ni. The advantage of such an approach is the possibility to take into account the laser radiation interaction with the spins and thus characterize the magnetic contribution to the total stress. We analyze the atomic displacements caused both by the ultrafast thermal expansion of the crystal lattice and by the demagnetization process due to the heating of a certain area of the sample by an ultrashort laser pulse. Subsequently, an attempt is made to propose mathematical expressions for describing the corresponding total stress. The lattice and magnetic contributions have been evaluated, whereupon the former is found to be much greater than the latter.

We use the short-time inference scheme [Manikandan et al., Phys. Rev. Lett. 124, 120603 (2020)], obtained within the framework of stochastic thermodynamics, to infer a lower bound to entropy production rate from flickering data generated by interference reflection microscopy of HeLa cells. We can clearly distinguish active cell membranes from their adenosine-triphosphate-depleted selves and even spatiotemporally resolve activity down to the scale of about 1 $\mu \mathrm{m}$. Our estimate of activity is model independent.

Understanding the mechanisms of cell-fate determination in neural development is pivotal for advancing regenerative medicine and addressing neurodegenerative diseases. Cell-fate determination is controlled by the underlying gene expression networks, which are further regulated by the three-dimensional chromosome structures. During neural development, chromosomes progressively adapt their structures to accommodate the requisite gene expressions. However, elucidating the pathways of chromosome structural dynamics during these transitions remains a grand challenge. In this study, we employed the data-driven coarse-grained molecular dynamics simulations, coupled with the nonequilibrium landscape-switching model, to quantify the chromosome structural dynamics during human neural development. We focused on a simplified human neural developmental system, comprising of cell differentiation, reprogramming, and transdifferentiation among the neural progenitor cell (NPC), the glia cell, and the neuron cell. We identified significant large-scale chromosome structural reorganizations during cell-state transitions. From the chromosome structural perspective, the transdifferentiation processes between the glia and neuron cells exhibited nonmonotonic behaviors characterized by an initial increase followed by a subsequent decrease in cell stemness. The transdifferentiation appeared to share the same routes of differentiation after passing through the NPC. Additionally, our findings revealed that the chromosome structural dynamical pathways at the scale of topologically associating domains exhibited little overlap, in contrast to the ones at the long-range regions. This suggests that the active, ATP-driven molecular processes play dominant roles in modulating topologically associating domain (TAD) structures, while the compartmental segregation in chromosomes is primarily governed by the passive phase separation. Our study offers a theoretical exploration of neural cell-fate determination from the chromosome structural perspective, paving a way for potential applications in neuroregeneration.

We report on the observation of the circular ratchet effect excited by terahertz laser radiation in a specially designed two-dimensional metamaterial consisting of a graphene monolayer deposited on a few-layer graphene gate patterned with an array of triangular antidots. We show that a periodically driven Dirac fermion system with spatial asymmetry converts the a.c. power into a d.c. current, whose direction reverses when the radiation helicity is switched. The circular ratchet effect is demonstrated for room temperature and a radiation frequency of 2.54 THz. It is shown that the ratchet current magnitude can be controllably tuned by the patterned and uniform back gate voltages. The results are analyzed in the light of the developed microscopic theory considering electronic and plasmonic mechanisms of the ratchet current formation.

The parent compound ${\mathrm{BaBiO}}_3$ of bismuthate high-temperature superconductors (HTSCs) $\mathrm{BaBi}\left(\mathrm{Pb}\right){\mathrm{O}}_3$ and $\mathrm{Ba}\left(\mathrm{K}\right){\mathrm{BiO}}_3$ with perovskitelike structure exhibits unusual electronic and structural properties, which can be satisfactorily explained if we assume that all charge carriers are in the paired state. However, the prior experiments and the first-principle calculations only indirectly indicate the existence of paired charge carriers in ${\mathrm{BaBiO}}_3$. In this work, we report the direct evidence of initially paired electrons and holes in the upper antibonding Bi $6s-\mathrm{O}2p_{{\sigma }^{*}}$ orbital of the neighboring octahedral complexes in the ground state of ${\mathrm{BaBiO}}_3$ using the time-resolved x-ray absorption spectroscopy (XAS) to monitor the electron dynamics after the femtosecond resonant 633 nm laser excitation. We observe strong changes in the oxygen $K$-edge XAS preedge region, defined by the $\mathrm{Bi}6s-\mathrm{O}2p_{{\sigma }^{*}}$ orbitals. We interpret them as a fast ($\le 0.3$ ps) breaking of charge carrier pairs and slower (0.3–0.8 ps) lattice rearrangement from the distorted monoclinic structure into the new metastable state with a cubic lattice, which persists at least up to 60 ps after the excitation. Analysis of the intermediate state at the fast excitation shows that the bond disproportionation and monoclinic distortion of ${\mathrm{BaBiO}}_3$ structure are energetically favorable due to the charge carrier pairing. Thus the compound ${\mathrm{BaBiO}}_3$ forms a new quantum state that we define as a local pair density wave. Taking into account a large number of similarities between bismuthate and cuprate high-temperature superconductors, we believe that our work will give a new impetus to understanding the nature of superconductivity in perovskite HTSCs.

We establish the quantum mechanics of composite fermions based on the dipole picture initially proposed by Read. It comprises three complimentary components: a wave equation for determining the wave functions of a composite fermion in ideal fractional quantum Hall states and when subjected to external perturbations, a wave-function Ansatz for mapping a many-body wave function of composite fermions to a physical wave function of electrons, and a microscopic approach for determining the effective Hamiltonian of the composite fermion. The wave equation resembles the ordinary Schrödinger equation but has drift velocity corrections that are not present in the Halperin-Lee-Read theory. The wave-function Ansatz constructs a physical wave function of electrons by projecting a state of composite fermions onto a half-filled bosonic Laughlin state of vortices. Remarkably, Jain's wave-function Ansatz can be reinterpreted as the new Ansatz in an alternative wave-function representation of composite fermions. The dipole picture and the effective Hamiltonian can be derived from the microscopic model of interacting electrons confined in a Landau level, with all parameters determined. In this framework, we can construct the physical wave function of a fractional quantum Hall state deductively by solving the wave equation and applying the wave-function Ansatz, based on the effective Hamiltonian derived from first principles, rather than relying on intuition or educated guesses. For ideal fractional quantum Hall states in the lowest Landau level, the approach reproduces the well-established results of the standard theory of composite fermions. We further demonstrate that the reformulated theory of composite fermions can be easily generalized for flat Chern bands.

Using quantum systems as sensors or probes has been shown to greatly improve the precision of parameter estimation by exploiting unique quantum features such as entanglement. A major task in quantum sensing is to design the optimal protocol, i.e., the most precise one. It has been solved for some specific instances of the problem, but in general even numerical methods are not known. Here, we focus on the single-shot Bayesian setting, where the goal is to find the optimal initial state of the probe (which can be entangled with an auxiliary system), the optimal measurement, and the optimal estimator function. We leverage the formalism of higher-order operations to develop a method based on semidefinite programming that finds a protocol that is close to the optimal one with arbitrary precision. Crucially, our method is not restricted to any specific quantum evolution, cost function, or prior distribution, and thus can be applied to any estimation problem. Moreover, it can be applied to both single-parameter or multiparameter estimation tasks. We demonstrate our method with three examples, consisting of unitary phase estimation, thermometry in a bosonic bath, and multiparameter estimation of an SU(2) transformation. Exploiting our methods, we extend several results from the literature. For example, in the thermometry case, we find the optimal protocol at any finite time and quantify the usefulness of entanglement.

We propose a new platform to detect signatures of the presence of Majorana bound states (MBSs) in the Fraunhofer pattern of Josephson junctions featuring quantum spin Hall edge states on the normal part and Majorana bound states at the NS interfaces. We use a tight-binding model to demonstrate a drastic change in the periodicity of the Fraunhofer pattern when comparing trivial and nontrivial regimes. We explain these results in terms of the presence of additional parallel-spin electron-hole reflections, which due to the spin-momentum locking, occur as cross Andreev reflections, accumulating a different magnetic flux and yielding a change in the Fraunhofer periodicity. We show that this detection scheme exhibits some advantages compared to previous ones as it is robust against disorder and finite temperature and works in equilibrium. Furthermore, we introduce a scattering model that captures the main results of the microscopic calculations with MBSs and extend our discussion to the main differences found using accidental zero-energy Andreev bound states.

Random matrix theory is a powerful tool for understanding spectral correlations inherent in quantum chaotic systems. Despite diverse applications of non-Hermitian random matrix theory, the role of symmetry remains to be fully established. Here, we comprehensively investigate the impact of symmetry on the level statistics around the spectral origin—hard-edge statistics—and expand the classification of spectral statistics to encompass all the 38 symmetry classes of non-Hermitian random matrices. Within this classification, we discern 28 symmetry classes characterized by distinct hard-edge statistics from the level statistics in the bulk of spectra, which are further categorized into two groups, namely, the Altland-${\mathrm{Zirnbauer}}_0$ classification and beyond. We introduce and elucidate quantitative measures capturing the universal hard-edge statistics for all the symmetry classes. Furthermore, through extensive numerical calculations, we study various open quantum systems in different symmetry classes, including quadratic and many-body Lindbladians, as well as non-Hermitian Hamiltonians. We show that these systems manifest the same hard-edge statistics as random matrices and that their ensemble-average spectral distributions around the origin exhibit emergent symmetry conforming to the random-matrix behavior. Our results establish a comprehensive understanding of non-Hermitian random matrix theory and are useful in detecting quantum chaos or its absence in open quantum systems.

We investigate the effect of nuclear quantum effects (NQEs) of hydrogen atoms on the elasticity of ice VII at high pressure and ambient-temperature conditions using ab initio path-integral molecular dynamics (PIMD) calculations. We find that the NQEs of hydrogen contribute to the transition of ice VII from a static disordered structure to a dynamically disordered structure at pressures exceeding 40 GPa. This transition is characterized by a nonlinear increase in the elastic constants. A comparison of ab initio molecular dynamics, and PIMD calculations shows that NQEs increase the elastic constants of ice by about 20% at 70 GPa and 300 K.

Despite significant advancements in continuous-variable quantum key distribution (CV-QKD), practical CV-QKD systems can be compromised by various attacks. Consequently, identifying new attack vectors and countermeasures for CV-QKD implementations is important for the continued robustness of CV-QKD. In particular, as CV-QKD relies on a public quantum channel, vulnerability to communication disruption persists from potential adversaries employing denial-of-service (DoS) attacks. Inspired by DoS attacks, this paper introduces a threat in CV-QKD called the channel amplification (CA) attack, wherein Eve manipulates the communication channel through amplification. We specifically model this attack in a CV-QKD optical fiber setup. To counter this threat, we propose a detection and mitigation strategy. Detection involves a machine learning (ML) model based on a decision tree classifier, classifying various channel tampering attacks, including CA and DoS attacks. For mitigation, Bob, postselects quadrature data by classifying the attack type and frequency. Our ML model exhibits high accuracy in distinguishing and categorizing these attacks. The CA attack's impact on the secret key rate (SKR) is explored concerning Eve's location and the relative intensity noise of the local oscillator (LO). The proposed mitigation strategy improves the attacked SKR for CA attacks and, in some cases, for hybrid CA-DoS attacks. Our study marks an application of both ML classification and postselection in this context. These findings are important for enhancing the robustness of CV-QKD systems against emerging threats on the channel.

The ability of quantum computers to overcome the exponential memory scaling of many-body problems is expected to transform quantum chemistry. Quantum algorithms require accurate representations of electronic states on a quantum device, but current approximations struggle to combine chemical accuracy and gate efficiency while preserving physical symmetries, and rely on measurement-intensive adaptive methods that tailor the wave function Ansatz to each molecule. In this contribution, we present a symmetry-preserving and gate-efficient Ansatz that provides chemically accurate molecular energies with a well-defined circuit structure. Our approach exploits local qubit connectivity, orbital optimization, and connections with generalized valence bond theory to maximize the accuracy that is obtained with shallow quantum circuits. Numerical simulations for molecules with weak and strong electron correlation, including benzene, water, and the singlet-triplet gap in tetramethyleneethane, demonstrate that chemically accurate energies are achieved with as much as 84% fewer two-qubit gates compared to state-of-the-art adaptive Ansatz techniques.

We explore the effects of driving a cavity at a large photon number in a circuit-QED experiment where the “matterlike” part corresponds to a unique Andreev level in a superconducting weak link. The three many-body states of the weak link, corresponding to the occupation of the Andreev level by 0, 1, or 2 quasiparticles, lead to different cavity frequency shifts. We show how the nonlinearity inherited by the cavity from its coupling to the weak link affects the state discrimination and the photon number calibration. Both effects require treating the evolution of the driven system beyond the dispersive limit. In addition, we observe how transition rates between the circuit states (quantum and parity jumps) are affected by the microwave power, and compare the measurements with a theory accounting for the “dressing” of the Andreev states by the cavity.

The olfaction begins when odorant molecules stimulate a finite number of receptor types in the olfactory neurons. According to the recent connectomics data of the Drosophila olfactory system, the olfactory neural circuit is multilayered and there is an overall dimensionality reduction from the input to output layer. Compressed sensing (CS) is an algorithm that enables the recovery of high-dimensional signals from the data compressed in a lower dimension when the representation of such signals is sufficiently sparse. By analyzing the recent Drosophila connectomics data, we find that the organization of the Drosophila olfactory system effectively satisfies the necessary conditions for CS to work. The neural activity profile of projection neurons (PNs) can be faithfully recovered from a low-dimensional response profile of mushroom body output neurons (MBONs), which can be reconstructed using the electrophysiological recordings of a wide range of odorants. By leveraging the residuals calculated between the measured and the predicted MBON responses, we visualize the perceptual odor space using the residual spectrum and discuss the differentiability of an odor from others. Our study highlights the sparse coding of odor to the receptor space as an essential component for odor identifiability, clarifying the principles underlying the concentration-dependent odor percept. Further, simultaneous exposure of the olfactory system to many different odorants saturates the neural activity profile of PNs, significantly degrading the capacity of signal recovery and resulting in a perceptual state analogous to “olfactory white.” Our study applying CS to the real connectomics data encompassing the neural circuitry from PNs to MBONs via Kenyon cells provides quantitative insights into the neural signal processing and odor representation in the inner brain of Drosophila.

Quantum computers are operated by external driving fields, such as lasers, microwaves, or transmission lines, that execute logical operations on multiqubit registers, leaving the system in a pure state. However, the drive and the logical system might become correlated in such a way that, after tracing out the degrees of freedom of the driving field, the output state will not be pure. Previous works have pointed out that the resulting error scales inversely with the energy of the drive, thus imposing a limit on the energy efficiency of quantum computing. In this study, focusing on the Jaynes-Cummings model, we show how the same scaling can be seen as a consequence of two competing phenomena: the entanglement-induced error, which grows with time, and a minimal time for computation imposed by quantum speed limits. This evidence is made possible by quantifying, at any time, the computation error via the spectral radius associated with the density operator of the logical qubit. Moreover, we also prove that, in order to attain a given target state at a chosen fidelity, it is energetically more efficient to perform a single driven evolution of the logical qubits rather than to split the computation in subroutines, each operated by a dedicated pulse.

In the kagome superconductors $A{\mathrm{V}}_3\mathrm{S}{\mathrm{b}}_5$ ($A$ = K, Rb, Cs), understanding the charge-density-wave (CDW) state and its entanglement with the superconducting ground state is still a challenging issue. Here, by measuring the electrical transport, magnetic susceptibility, Hall effect, and ${}^{51}\mathrm{V}$ nuclear magnetic resonance (NMR), the evolution of superconductivity (SC) and the CDW is comprehensively studied in $\mathrm{Cs}{\left({\mathrm{V}}_{1-x}\mathrm{M}{\mathrm{o}}_x\right)}_3\mathrm{S}{\mathrm{b}}_5$. In contrast with previously reported results for other doped cases, the CDW transition temperature slightly increases to ∼100 K with increasing Mo doping. Meanwhile, the SC is quickly suppressed and vanishes above $x=0.02$. The anomalous Hall effect (AHE), which is tied to the exotic nature of the CDW state in pristine $\mathrm{Cs}{\mathrm{V}}_3\mathrm{S}{\mathrm{b}}_5$, is also strongly suppressed and completely disappears above $x=0.07$. Further ${}^{51}\mathrm{V}$ NMR investigation on the CDW state in $\mathrm{Cs}{\left({\mathrm{V}}_{0.95}\mathrm{M}{\mathrm{o}}_{0.05}\right)}_3\mathrm{S}{\mathrm{b}}_5$ indicates that a short-range stripelike CDW evolves from the original triple-$Q$ CDW state with increasing Mo doping, which largely reduces the density of states at the Fermi level. This result provides a self-consistent explanation for the disappearance of both SC and the AHE by increasing Mo doping, which offers insights into the competitive behavior between SC and the CDW state in the kagome superconductors $A{\mathrm{V}}_3\mathrm{S}{\mathrm{b}}_5$.