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From the perspective of resource theory, it is interesting to achieve the same quantum task using as few quantum resources as possible. Semiquantum key distribution (SQKD), which allows a quantum user to share a confidential key with a classical user who prepares and operates qubits on only one basis, is an important example for studying this issue. To further limit the quantum resources used by users, in this paper, the first SQKD protocol is constructed, which restricts the quantum user to prepare quantum states on only one basis and removes the classical user's measurement capability. Furthermore, it is proven that the constructed protocol is secure against the restricted attack by deriving a key rate expression of the error rate in the asymptotic scenario. The work in this paper provides inspiration for achieving quantum superiority with minimal quantum resources. [ABSTRACT FROM AUTHOR]

A recent analysis of two handwritten sheets of paper by Henry Cavendish (1731–1810) reveals the details of his calculation of the deflection of light induced by the gravitational field of isolated celestial bodies. Except for a few lines from one of these pages, where Cavendish communicated the result, the two documents have never been published. This gave rise to speculations about how, if at all, Cavendish derived his formula for the deflection angle by his own calculations. Such doubts are dispelled and it is demonstrated how Cavendish, in these documents, applied Newtonian mechanics to the corpuscles of light. A recent analysis of two handwritten sheets of paper by Henry Cavendish (1731–1810) reveals the details of his calculation of the deflection of light induced by the gravitational field of isolated celestial bodies. Except for a few lines from one of these pages, where Cavendish communicated the result, the two documents have never been published. [ABSTRACT FROM AUTHOR]

Rudolph Clausius is well known as a pioneer of the mechanical theory of heat (1857) and as the creator of the concept of entropy (1865). Oftentimes, he is also called the discoverer of the second law of thermodynamics although some argue that this law was already established by Sadi Carnot in 1824 (while still based on the caloric theory). But beyond any doubt, it was Clausius who gave in 1850 the first mathematically correct formulation of the first law (in its differential form that is still valid today, dQ = dU + pdV) and a particularly stringent exposition of both the necessity and independence of the two laws, indeed a logical masterpiece. This paper focuses on his concept of mathematical physics for the development of theoretical physics, contributions that have changed physics well beyond the field of thermodynamics. [ABSTRACT FROM AUTHOR]

This paper explores the groundbreaking contributions of Hermann von Helmholtz and Erwin Schrödinger to the geometry of color space ‐a 3D space that correlates color distances with perceptual differences. Drawing upon his expertise in non‐Euclidean geometry, physics, and psychophysics, Helmholtz introduced the first Riemannian line element in color space between 1891 and 1892, inaugurating a new line of research known as higher color metric, a term coined by Schrödinger in 1920. During his tenure at the University of Vienna, Schrödinger extensively worked on color theory and rediscovered Helmholtz's forgotten line element. In his 1920 papers titled "Grundlinien einer Theorie der Farbmetrik im Tagessehen," published in the Annalen der Physik, Schrödinger elucidated certain shortcomings in Helmholtz's model and proposed his refined version of the Riemannian line element. This study delves into this captivating chapter in the history of color science, emphasizing the profound impact of Helmholtz's and Schrödinger's work on subsequent research in color metrics up to the present day. [ABSTRACT FROM AUTHOR]

In this paper, the higher energy levels of the transmon qubit are taken into consideration to investigate the continuous variable entanglement generation between the transmon qubit and the single‐mode cavity. Based on the framework of cavity Quantum Electrodynamics (QED), the authors show the entanglement generation depends on the driving field intensity, coupling strength, cavity field frequency, and qubit frequency. The numerical results show that strong entanglement can be generated by properly tuning these parameters. It is hoped that the results presented in this paper may lead to a better understanding of quantum entanglement generation in cavity QED systems and provide new perspectives for further research in quantum information processing. [ABSTRACT FROM AUTHOR]

This paper proposes a 32‐tupling frequency millimeter‐wave (MMW) filter‐free system based on four Mach‐Zehnder Modulators (MZM) connected in parallel and cascaded with a simple radio‐fiber (RoF) link structure. The four MZMs are all at the maximum transmission point (MATP), and the radio frequency (RF) driving voltage phase difference between MZMs is π /2. The center carrier is suppressed by using an optical attenuator (OATT) and an optical phase shifter (OPS). Two parallel MZMs can generate ±8th order and ±12th order optical sidebands, and the ±4th order optical sidebands can be suppressed by adjusting the modulation index m of the MZM, using cascaded two dual‐parallel MZMS(DPMZM) and the phase difference of the RF signal source is π/4 to generate ±16th order optical sidebands. The theoretical analysis and simulation experiments are performed for the scheme proposed in this paper. The results show that the simulated and theoretical values of the optical sideband suppression ratio (OSSR) for ±16th order optical sideband signals are 60.02 and 59.96 dB, respectively, and the simulated and theoretical values of the RF sideband suppression ratio (RFSSR) for the 32‐tupling MMW signal are 56.34 and 53.94 dB, respectively. [ABSTRACT FROM AUTHOR]

The energy conditions in general relativity are introduced to establish powerful theorems without having to restrict their applicability to specific choices of the stress‐energy tensor. They are famously invoked, e.g., to prove the singularity theorems of Penrose and Hawking, but have also been applied elsewhere, including various tests of certain cosmological theories. These conditions have become somewhat controversial, however, because they appear to be violated by commonly accepted scenarios, such as inflation shortly after the Big Bang and late‐time acceleration of the cosmic expansion. But accommodating these processes by abandoning all of the energy conditions will promote other disquieting possibilities, including the breakdown of causality with traversable wormholes and closed timeloops. This paper advocates for the opposite viewpoint, demonstrating that the 'numen' scalar field, derived from the zero active mass condition in general relativity, satisfies all of the energy conditions in the early Universe. This unique feature among scalar fields adds to its success in accounting for the observed properties of the cosmic microwave background better than its inflationary counterpart. Specifically, numen's complete consistency with all of the energy conditions, and inflation's violation of at least one of them, provides additional justification for theoretically favoring the former over the latter. [ABSTRACT FROM AUTHOR]

In this paper, a metastructure multifunctional device for circular‐to‐linear polarization conversion (PC) and perfect absorption is proposed in which the electrical conductivity of the silicon material is controlled by light, thus changing the function of the device. The paper also explores three methods of optimizing bandwidth and their mechanisms, which are analyzed by means of current and energy density diagrams. The unit structure of this device adopts a 2 × 2 array, which is used for differentiated reflection of circular polarization waves, and forms linear polarization waves after reflection. In the other state, ultrawideband absorption can be achieved by changing the conductivity of silicon by external optical pumping, and the bandwidth is widened by inserting air resonators. In general, the device can form a PC at 0.89–1.31 THz with a relative bandwidth of 38% when there is no illumination. The resulting linear polarization wave has an axial ratio greater than 19 dB. When the silicon is excited by light resulting in a stable conductivity of around 9000 S m−1, the absorption band is 0.89–2.01 THz, the relative bandwidth is 77%, and the absorption rate is above 90%. This device can be used for communication, electromagnetic cloaking, and modulation. [ABSTRACT FROM AUTHOR]

Electrodynamics on curved surfaces, as a developed theory, has analogously become a new experimental verification of light transmission in general relativity. The thermal effect of an optical field on a specific 2D surface with constant Gaussian curvature is described in this paper. By considering the analogy between Schrodinger equation and Helmholtz equation under the paraxial approximation, the "quantized" momentum field is generated from the light transmitting on a curved surface by using the effective potential approach, and when decreasing the number of photons until n=0$n = 0$ is thought about, a temperature of Hawking‐like radiation is obtained. The creation process of radiation is also investigated, which is the scattering of light as it travels from a surface of positive curvature to a surface of negative curvature. The derived temperature of radiation field is also equivalent to the event horizon scattering explanation of Hawking radiation. The research may provide new perspectives for Hawking radiation and thermal lens. [ABSTRACT FROM AUTHOR]

The third observing run (O3) of Advanced LIGO and Advanced Virgo started in April 2019 and ended in March 2020 due to the pandemic. From the O3 run three catalogs of compact binary mergers, GWTC‐2, GWTC‐2.1, and GWTC‐3, that include also some exceptional events, are produced by the LIGO/Virgo Collaboration. The paper will review the science results about compact binary mergers during the O3 run and the follow‐up of gravitational wave candidate events involving the whole electromagnetic spectrum and neutrinos. No confirmed counterpart is found during the O3 run for any candidate. The impact of detected events on astrophysics and cosmology will also be discussed. The paper will also briefly summarize additional multi‐messenger investigations involving candidates not initially associated to gravitational events. [ABSTRACT FROM AUTHOR]

In this paper, a continuous variable (CV) measurement‐device‐independent (MDI) quantum key distribution (QKD) protocol using Gaussian modulated coherent states is proposed. The MDI is first proposed to resist the attacks on the detection equipment by introducing an untrusted relay. However, the necessity of propagation of local oscillator between legitimate users and the relay makes the implementation of CV‐MDI‐QKD highly impractical. By introducing the plug‐and‐play (P&P) technique into CV‐MDI‐QKD, the problems of polarization drifts caused by environmental disturbance and the security loopholes during the local oscillator transmission are solved naturally. The proposed scheme is superior to the previous CV‐MDI‐QKD protocol on the aspect of implementation. The security bounds of the P&P CV‐MDI‐QKD under the Gaussian collective attack are analyzed. It is believed that the technique presented in this paper can be extended to quantum network. [ABSTRACT FROM AUTHOR]

In this paper, an analytical expression of Airy beams near a black hole is derived by general relativity concepts. This paper demonstrates the self‐acceleration and the self‐healing properties of Airy beams near a black hole with different Schwarzschild radii. It shows, during transmission, that the equivalent acceleration near a black hole decreases to a minimum negative value, then increases and eventually approaches zero. After propagating a certain distance, the trajectories of Airy beams approaching a black hole may no longer travel along parabolas, but rather almost straight lines due to the existence of the strong gravitational field. The shapes of the wave structure of Airy beams remain unvarying during the transmission, which indicates that the nondiffraction characteristic is still present. Moreover, the self‐healing property of Airy beams near a black hole gradually disappears with the increase of the strength of the gravitational field, because the energy flow to the major lobe is prevented by the gravitational field of the black hole. These intriguing features may open new prospects in the fields of nanophotonic optics, relativistic effects, transformation optics, and so on. [ABSTRACT FROM AUTHOR]

In this paper, six kinds of periodic optical waveguide networks are designed to study the influence of three‐order parity–time‐symmetric (PT‐symmetric) substructures on the singular optical characteristics. It is found that different characteristics correspond to different PT‐symmetric substructures, and new singular optical characteristics are produced by adjusting the PT‐symmetric substructures. This work demonstrates that these six kinds of systems can create novel quasi‐blackbody, super reflection, and new total reflection, which are significantly different from the corresponding traditional properties and have not been reported yet. These findings may deepen the understanding of PT‐symmetric optical systems and optical waveguide networks, and these new characteristics may possess potential applications in the design of multifunctional optical structures with efficient information processing. [ABSTRACT FROM AUTHOR]

Quantitative climate mobility research has, so far, focused primarily on climate change impacts on migration outcomes. This focus has led to a separation between quantitative climate migration research and the broader field of migration studies. In this paper ways are proposed for quantitative research to better address the complexity in the relationship between climate change and mobility. First technical suggestions are presented to improve upon migration model setups and designs and highlight promising developments. Then it is argued that quantitative methodologies can broaden the scope of research inquiries by examining how climate mitigation and adaptation efforts influence mobility, as well as assessing how mobility itself impacts vulnerability. [ABSTRACT FROM AUTHOR]

In this paper, the introduction of a novel type of electron beams known as electron odd‐Pearcey Gaussian beams (EOPGBs) is presented. For the first time, the dynamics of EOPGBs are explored propagating in both free space and a constant magnetic field by employing the Schrödinger equation. The investigation reveals that the electron beams exhibit remarkable auto‐focusing characteristics in these two media, and the focal length can be controlled by adjusting certain parameters. Additionally, in a constant magnetic field, EOPGBs exhibit intriguing properties, notably the dual auto‐focusing property, which sets them apart from other known electron beams. The probability currents and distribution factors are used to provide a theoretical explanation for the aforementioned features of EOPGBs. Furthermore, the conclusions are consistent with the results obtained from numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, symmetric Pearcey Gaussian beams (SPGBs) are studied in a Kerr medium. By varying the initial input power, the autofocusing ability of the beams is investigated, to find a clear restrictive relationship between the breath‐like structure and the initial input power. The critical collapse power is investigated when SPGBs change from discrete beams to regular breath‐like structure. Finally, the transmission of SPGBs is discussed under different phase modulation when SPGBs are affected by astigmatic, the whole beam is rotated and the angle of rotation can be controlled. [ABSTRACT FROM AUTHOR]

The adaptive voter model is widely used to model opinion dynamics in social complex networks. However, existing adaptive voter models are limited to only pairwise interactions and fail to capture the intricate social dynamics that arises in groups. This paper extends the adaptive voter model to hypergraphs to explore how forces of peer pressure influence collective decision‐making. The model consists of two processes: individuals can either consult the group and change their opinion or leave the group and join a different one. The interplay between those two processes gives rise to a two‐phase dynamics. In the initial phase, the topology of the hypergraph quickly reaches a new stable state. In the subsequent phase, opinion dynamics plays out on the new topology depending on the mechanism by which opinions spread. If the group always follows the majority, the network rapidly converges to fragmented communities. In contrast, if individuals choose an opinion proportionally to its representation in the group, the system remains in a metastable state for an extended period of time. The results are supported both by stochastic simulations and an analytical mean‐field description in terms of hypergraph moments with a moment closure at the pair level. [ABSTRACT FROM AUTHOR]

In this paper, the Gibbons and Werner technique is used to calculate the weak deflection angle for the black hole solution under the effects of Einstein–Gauss–Bonnet gravity. The Gauss–Bonnet theorem in the limits of weak field is used to evaluate the Gaussian optical curvature in order to obtain the results. The visual effects of the deflection angle on the impact parameter is also looked at and the smallest radius in the non‐plasma/plasma medium. Moreover, in order to check the consistency of the results concerning the weak deflection angle, the Keeton and Petters approach is applied to study the deflection angle, which is the expansion of series with a single mass variable, which can be directly addressed by using the post–post Newtonian framework. Furthermore, the deflection angle and shadow under the influence of the plasma is examined by using the motion of particle in a non‐magnetized plasma and pressure‐free plasma medium as described by the new ray‐tracing algorithm. It is shown that plasma as well as Einstein–Gauss‐Bonnet gravity corrections are affected by shadows. [ABSTRACT FROM AUTHOR]

This paper analytically and numerically proposes the propagation dynamics of the symmetric Pearcey Gaussian vortex beam (SPGVB) in the uniformly moving parabolic potential. The optical vortex located in the initial plane produces a vortex channel in the presence of the uniformly moving parabolic potential, called the vortex trajectory. The vortex trajectory can be manipulated dynamically by configuring different combinations of the parameters, and the optical intensity and the focal position can also be affected. Moreover, the spatial dynamic vortex trajectory is derived analytically, and the 2D on‐axis and off‐axis vortex scenarios are also presented. Our work expands the methods of the vortex trajectory manipulation and may broaden more practical potential applications in the particle manipulation. [ABSTRACT FROM AUTHOR]

In this paper, a 1D nonlinear plasma photonic crystal (NPPC) structure composed of polarized ferroelectric crystals and nonlinear plasma periodic alternation is proposed. The transfer matrix method is employed to analyze the second harmonic generation (SHG) problem of this structure. In the designed NPPCs, the fundamental wave (FW) operates in the gigahertz (GHz) band and the nonlinear plasma is controlled by an external high‐intensity control wave (CW). Numerical simulations are performed to investigate the effects of different incident angles and external CW intensities on the total conversion efficiency (T‐con) of the second harmonic wave (SHW). Additionally, the internal electric field distribution and incident light intensity within the nonlinear structure are analyzed. The importance of the relationship between the FW frequency and photonic band gap (PBG) in enhancing SHG is summarized. The results demonstrate that the optimal structure can be obtained by changing the structural parameters, such that the FW and SHW are tuned to the edge of the PBG. At this point, the electromagnetic field density is large, the group velocity is small, the local field is enhanced, and the nonlinear optical interaction is increased, resulting in a significant increase in the T‐con of the SHW. [ABSTRACT FROM AUTHOR]

The emergence of new materials and fabrication techniques provides progress in the development of advanced photonic and communication devices. Transition metal dichalcogenides (e.g., molybdenum disulfide, MoS2) are novel materials possessing unique physical and chemical properties promising for optical applications. In this paper, a metasurface composed of particles made of bulk MoS2 is proposed and numerically studied considering its operation in the near‐infrared range. In the bulk configuration, MoS2 has a layered structure being a uniaxial anisotropic crystal demonstrating an optical birefringence property. It is supposed that the large‐scale and uniform MoS2 layers are synthesized in a vertical‐standing morphology, and then they are patterned into a regular 2D array of disks to form a metasurface. The natural anisotropy of MoS2 is utilized to realize the splitting of electric and magnetic dipole modes of the disks while optimizing their geometric parameters to bring the desired modes into overlap. At the corresponding resonant frequencies, the metasurface behaves as either an electric or a magnetic mirror, depending on the polarization of incident light. Based on the extraordinary reflection characteristics of the proposed metasurface, it can be considered an alternative to traditional mirrors and optical splitters when designing compact and highly efficient metadevices, which provide polarization and phase manipulation of electromagnetic waves on a subwavelength scale. [ABSTRACT FROM AUTHOR]

In this paper, the deflection angle of light by traversable wormholes, which are supported by the three‐form fields, are studied. The specific forms of the redshift and shape functions that produce results compatible with the energy conditions at throat of the wormholes are used. Having used the well‐defined parameter sets of the three‐form wormholes, the photon geodesic motion is investigated under the effective potential of the wormhole background. As a result, it is discovered that the radius of the photon sphere can be used to analyze the geometrical structures of a physical wormhole. The analytical form of the effective potential is used to figure out a deflection angle of light caused by wormholes with the three‐from fields. In this work, the relativistic images generated from the wormholes are also constructed. [ABSTRACT FROM AUTHOR]

Wormholes (WHs) are hypothetical topologically non‐trivial spacetime structures that can be freely traversed by observers and connect two asymptotic regions or infinities. From the current theoretical development, the prospect of their existence is challenging but cannot be excluded. In this paper, generalized Ellis–Bronikov (GEB) traversable WH geometries for static and spherically symmetric spacetime in the background of f(R)$f(R)$ gravity is explored. First, the Tsujikawa‐like f(R)$f(R)$ model and the shape function for the GEB model is considered, which depend on a sequence of simple Lorentzian WHs with two parameters: a free even integer exponent, n, besides the throat radius, r0. One also consider that these WHs are generated by dark matter galactic halos (DMGHs), based on the three most common phenomenological models, viz., Navarro–Frenk–White (NFW), Thomas–Fermi (TF), and pseudo‐isothermal (PI). In this concern, the satisfaction of the energy conditions (ECs) which are dependent on the dark matter (DM) models, viz., dominant energy condition (DEC) and strong energy condition (SEC) and those which are not dependent viz., null energy condition (NEC) and WEC at the WH throat and its neighborhood is investigated. Finally, the presence of exotic matter is confirmed by the violation of the NEC in all cases, revealing the supremacy and physical acceptability to support the existence of the WHs and making them compatible and traversable in Tsujikawa's‐like f(R)$f(R)$ model. [ABSTRACT FROM AUTHOR]

This paper presents an accelerating cosmological model by constraining the free parameters using the cosmological datasets in an extended symmetric teleparallel gravity for the flat and anisotropic space‐time. It employs a time variable deceleration parameter that behaves early deceleration and late time acceleration in the form of a hybrid scale factor (HSF). It obtains the present values of deceleration parameter and analyzes the late time behavior of the Universe based on the best‐fit values of the free parameters. It derives the dynamical parameters of the model and obtains the equation of state parameter at present in the quintessence region; however, at late time it approaches to ΛCDM. The energy conditions are also analyzed to validate the modified gravity and it finds that the strong energy condition is violating. It establishes the importance of a hybrid scale factor in the late time cosmic phenomena issue. [ABSTRACT FROM AUTHOR]

While the quantum metrological advantages of performing non‐Gaussian operations on two‐mode squeezed vacuum (TMSV) states have been extensively explored, similar studies in the context of two‐mode squeezed thermal (TMST) states are severely lacking. This paper explores the potential advantages of performing non‐Gaussian operations on TMST state for phase estimation using parity detection‐based Mach–Zehnder interferometry and compares it with the TMSV case. To this end, a realistic photon subtraction, addition, and catalysis model is considered. A unified Wigner function of the photon subtracted, photon added, and photon catalyzed TMST state is derived, which is used to obtain the expression for the phase sensitivity. The results show that performing non‐Gaussian operations on TMST states can enhance the phase sensitivity for significant squeezing and transmissivity parameter ranges. Because of the probabilistic nature of these operations, it is of utmost importance to consider their success probability. When the success probability is considered, the photon catalysis operation performed using a high transmissivity beam splitter is the optimal non‐Gaussian operation. This contrasts with the TMSV case, where photon addition is observed as the most optimal. Further, the derived Wigner function of the non‐Gaussian TMST states will be useful for state characterization and various quantum protocols. [ABSTRACT FROM AUTHOR]

If gravity is quantized, one of the consequences may be that the spacetime coordinates are quantized and become noncommutative. The κ‐Minkowski spacetime is such kind of noncommutative spacetime. In this paper, the resonance interaction energy of a two‐atom system coupled with a fluctuating vacuum scalar field in the κ‐Minkowski spacetime is studied. It is found that the resonance interaction energy is dependent on the interatomic separation, the transition wavelength of the atoms, and the spacetime non‐commutativity. When the interatomic separation is small compared with a characteristic length determined by the spacetime non‐commutativity parameter and the transition wavelength, the resonance interaction energy is that in the Minkowski spacetime plus a correction due to the spacetime non‐commutativity. When the interatomic separation is comparable to or larger than the characteristic length, the resonance interaction energy cannot be organized in the form of a Minkowski term plus a correction, which indicates that the long‐range behavior of the vacuum in the κ‐Minkowski spacetime is fundamentally different from that in the Minkowski spacetime. [ABSTRACT FROM AUTHOR]

This paper proposes a novel approach to visualize the fractional orbital angular amentum (OAM) flow of light fields at the example of the Lommel tornado wave (LoTW) along the propagation direction in free space. The novel approach that is based on the transverse intensity distributions of the LoTWs can be used to identify and quantify the fractional OAM. The energy that is continuously distributed flexibly is controlled via the asymmetry factor and topological charge. Furthermore, the OAM density on concentric rings and chiral paths is employed to demonstrate convincingly as a manifestation of the energy flow. Such beams are anticipated to find potential applications in optical communication and optical micromanipulation. [ABSTRACT FROM AUTHOR]

Dielectric mirrors comprising thin‐film multilayers are widely used in optical experiments because they can achieve substantially higher reflectance compared to metal mirrors. Here, potential problems are investigated that can arise when dielectric mirrors are used at oblique incidence, in particular for focused beams. It is found that light beams reflected from dielectric mirrors can experience lateral beam shifts, beam‐shape distortion, and depolarization, and these effects have a strong dependence on wavelength, incident angle, and incident polarization. Because vendors of dielectric mirrors typically do not share the particular layer structure of their products, several dielectric‐mirror stacks are designed and simulated, and then the lateral beam shift from two commercial dielectric mirrors and one coated metal mirror is also measured. This paper brings awareness of the tradeoffs between dielectric mirrors and front‐surface metal mirrors in certain optics experiments, and it is suggested that vendors of dielectric mirrors provide information about beam shifts, distortion, and depolarization when their products are used at oblique incidence. [ABSTRACT FROM AUTHOR]

The formation and stability of solids and molecules is not possible without chemical bonds, which are divided into covalent, ionic, metallic, and van der Waals bonds. A special type of intermolecular bond is hydrogen bonding, which plays a crucial role for chemical, biological, and physical processes. However, hydrogen shows a far more complex behavior when it is present in solids. In this paper, it is shown that the chemical bonding of hydrogen atoms and molecules extends far beyond the simple picture of conventional, ionic, covalent, and multicenter bonds. The interaction of H with its host material is particularly important for hydrogen storage in metallic materials such as Ti3C2${\rm Ti}_{3}{\rm C}_{2}$ MXenes. Hydrogen atoms and H2${\rm H}_2$ molecules form multicenter bonds in Ti3C2${\rm Ti}_{3}{\rm C}_{2}$. On the surface and between two Ti3C2${\rm Ti}_{3}{\rm C}_{2}$ sheets this is limited to the formation of H–Ti bonds. However, H and H2${\rm H}_2$ on interstitial sites form multicenter bonds not only with nearest neighbor Ti atoms but also with carbon atoms. Interestingly, the H–C bonds are characterized by the formation of s–p hybrid orbitals. For H2${\rm H}_2$ molecules, multicenter bond formation is accompanied by an increase of the bond length to 2.07 and 1.85 Å for H2${\rm H}_2$ on the surface and at the interstitial site, respectively. On the other hand, placing H2${\rm H}_2$ between two sheets of Ti3C2${\rm Ti}_{3}{\rm C}_{2}$ leads to dissociation. For all H and H2${\rm H}_2$ complexes the vibrational eigenmodes are calculated. Their frequencies are in the range of 890 to 1610 cm−1${\rm cm}^{-1}$, which indicates that the bonds are remarkably strong. [ABSTRACT FROM AUTHOR]

The conservation of spectral asymmetry is a fundamental feature of the ideal four‐wave mixing process as it exists in a medium combining quadratic chromatic dispersion and third‐order nonlinearity. The robustness of this invariant in an experimental configuration where the excitation conditions of an optical fiber are sequentially updated, mimicking infinite propagation is tested in this paper. This theoretical and experimental study reveals the high sensitivity of the asymmetry to very slight deviations from the ideal case, and the idealized system behaves as an intermediate case between the ideal case of noncascaded four‐wave mixing and propagation in a system governed by the nonlinear Schrödinger equation is shown. [ABSTRACT FROM AUTHOR]

In this paper, the performance of a unidimensional continuous variable quantum key distribution protocol is analyzed using Gaussian modulated coherent state under fast fading channel. In the fast fading channel, both parties are connected in free space, resulting in a harsh propagation environment and pollution caused by atmospheric turbulence. This pollution makes it difficult for the communicators to determine the channel transmittance, which can only be estimated based on a probability distribution. To address this, only one modulator is used to code, which demonstrates performance equivalent to that of the symmetric modulated Gaussian coherent state protocol. The security of the protocol in the face of collective attacks is analyzed and it is proved that it can accept a certain amount of excessive channel noise while simplifying operations. Simultaneously, the impact of finite‐key length effects on the protocol is analyzed. It is also demonstrated that this protocol can reduce costs within an acceptable range of performance losses, making it more practical. [ABSTRACT FROM AUTHOR]

Hybrid entangled states (HES) have attracted significant attention and been utilized in various quantum information processing applications. However, like many other entangled states, maximally entangled HES may degrade to mixed states due to environmental noise and operational imperfections. In this paper, a hybrid entanglement purification protocol (HEPP) for the HES, which consists of photon‐number state and coherent state is proposed. This HEPP is designed to effectively purify a bit‐flip error occurring in any qubit of the HES. Furthermore, HEPP is extended to a general condition, say, the multi‐party scenario, and integrates the generation of HES into the HEPP. Moreover, if different initial mixed states are chosen, then the residual entanglement can be utilized to distill high‐quality entanglement. The HEPP has important applications in the future quantum information processing field. [ABSTRACT FROM AUTHOR]

In the paper, the possibility of two complete conversions is investigated, one is from the two‐photon hyperentangled Knill–Laflamme–Milburn (KLM) state to hyperentangled Bell states, the other is from three‐photon KLM state to the hyperentangled Greenberger–Horne–Zeilinger states, for photonic systems hyper‐encoded in polarization and spatial degrees of freedom assisted by error‐heralded quantum units (EHQUs). The system inhomogeneity and/or the imperfect photon scattering often restrict the performance of effective conversions of two types of hyperentangled states, and result in the reductions of the fidelity and the efficiency in tangible quantum information technologies. The polarization EHQU and spatial EHQU are two critical tools for actualizing two hyperentangled conversions in a heralded way, as the errors stemming from the system inhomogeneity and practically imperfect scattering are converted into efficacious responses of the detectors in our protocols. Thus, the fidelities of these conversion cases keep unchanged and have close to unity fidelities, which deepen the understanding of the properties of hyperentanglement. [ABSTRACT FROM AUTHOR]

In this paper, a new type of structured electron beam is introduced, which is the electron Airy tornado wave (eATW) with the characteristics of abrupt auto‐focusing and rotation property in free space. It is also found that the eATWs propagate periodically in a magnetic field, and their patterns of intensity distributions show the time‐like axial symmetry about a half‐period point in a period of time. Furthermore, the influence of the magnetic field's magnitude and direction on eATWs with different parameters has also been discussed. [ABSTRACT FROM AUTHOR]

In this paper, an ultra‐wideband chirality selective metastructure absorber is proposed that enables differential absorption and reflection of circularly polarized waves in the terahertz (THz) range. The structure achieves circular dichroism (CD) by using asymmetrically split metal rings as fundamental meta‐atoms. Most critically, the high impedance surface and air‐resonant cavities are inserted separately in the meta‐atoms and dielectric substrate to enhance CD and broaden the bandwidth of absorption. The metastructure absorber can achieve more than 90% absorption of right circularly polarized waves at 0.675–1.244 THz, and it can maintain more than 90% reflection of left circularly polarized waves at 0.607–1.229 THz without changing the direction of rotation. Besides, its CD can reach more than 80% at 0.687–1.213 THz with a relative bandwidth of 55.3%. Spin‐selective absorption, which is closely related to breaking chiral symmetry, is investigated through power loss distribution, wide‐angle incidence, and scan parameter optimization. The proposed strategy is further validated in the THz band, and the polarization selection and manipulation techniques can be applied to chiral sensing/radio‐thermometry, circular polarization detectors/lasers, and molecular spectroscopy. [ABSTRACT FROM AUTHOR]

With the tunability of the nematic liquid crystal (NLC), a broadband frequency reconfigurable and versatile metastructure (MS) is proposed and theoretically investigated in this paper, combining circular‐to‐linear (CTL) polarization conversion (PC) and circular‐to‐circular (CTC) PC simultaneously. The MS is composed of two via‐coupled modules, which can respond differently to the incident waves. Each module is connected utilizing a metal via a column, thus exceedingly enhancing the energy transmission and reducing the loss when transmitting. When the applied bias voltage (Vbias) is 0 V, the NCL molecules follow the initial orientation. The MS converts the incident right circular polarized (RCP) waves into linear polarized (LP) waves within 8.11–9.95 gigahertz (GHz) with a relative bandwidth of 20.38% and achieves the PC of left circular polarized (LCP) into RCP waves. As the Vbias reaches 20 V, the original operating interval reconfigures and shifts overall toward a lower frequency. The bandwidth of CTL is 7.66–9.02 GHz, and the CTC PC is broadened to 20.20%. Meanwhile, the structure justification is verified, and the inducing mechanism of PC is expounded. Possessing the merits of versatile collaborative processing and wide operating bands, such an MS is promising to be a polarization‐controlled application candidate and enrich multifunctional designs. [ABSTRACT FROM AUTHOR]

In this paper, the cosmological model of the Universe has been presented in f(Q)$f(Q)$ gravity and the parameters are constrained from the cosmological data sets. At the beginning, a well motivated form of f(Q)=α+βQn$f(Q) = \alpha + \beta Q^{n}$ has been employed, where α, β, and n are model parameters. The Hubble parameter is obtained in redshift with some algebraic manipulation from the considered form of f(Q)$f(Q)$. Then it is parameterized with the recent Hubble$\text{Hubble}$ data and Pantheon+SHOES$\text{Pantheon} + \text{SHOES}$ data using Markov chain Monte Carlo analysis. The obtained model parameter values are validated with the baryon acoustic oscillation data set. A parametrization of the cosmographic parameters shows the early deceleration and late time acceleration with the transition at zt≈0.75$z_\text{t}\approx 0.75$. The Om(z)$Om(z)$ diagnostics gives positive slope which shows that the model is in the phantom phase. Also the current age of the Universe has been obtained as, t0=13.85Gyrs$t_{0} = 13.85\nobreakspace \nobreakspace \text{Gyrs}$. Based on the present analysis, it indicates that the f(Q)$f(Q)$ gravity may provide an alternative to dark energy for addressing the current cosmic acceleration. [ABSTRACT FROM AUTHOR]

Conventionally, dynamical encirclement of exceptional points in non‐Hermitian systems is known to manifest a counterintuitive chiral state conversion. However, the prerequisite of such traits enclosing an exceptional point is broken when only encircling its proximity, preserving a still chiral switching. Research on the proximity‐encirclement in multistate systems is lacking. In this paper, a photonic‐waveguide‐array non‐Hermitian system is proposed to investigate the dynamics by encircling two exceptional points or their proximity. A series of encircling trajectories defined by the parametric equations are designed to steer the evolution of photonic modes in waveguides. The wave propagating along the waveguides is also simulated to capture this non‐Hermitian physics. The chiral behavior in proximity‐encirclement contrasts with the familiar encirclement of one exceptional point and exhibits the unexpected occurrence of nonadiabatic transitions. Furthermore, if two exceptional points are sufficiently encircled, the system will evolve to a stable final state earlier, as a symbol of the occurrence of the nonadiabatic transition. Such novel chiral conversion is maintained only if the encircling trajectories are located at adequate proximity. [ABSTRACT FROM AUTHOR]

Nonclassical effects in mesoscopic systems have attracted much attention recently. In this paper, it is shown that multiphonon bundle emission can be observed in a strong‐coupling cavity optomechanical system. Theoretical analysis shows that when the driving field is adjusted to nth‐order sideband excitation, the coupling between the cavity mode and the vibrational mode leads to super‐Rabi oscillations, and finally results in an n‐phonon bundles emission. Based on the current technology, this process can work in a wide range of parameters. Numerical simulation confirms the validity of the derivation. It is thought that this physical mechanism broadens the applications of cavity optomechanical system in realm of quantum phononics, such as in quantum metrology and phonon laser. [ABSTRACT FROM AUTHOR]

Chaos is important in nonlinear science and promotes the development of fundamental studies, such as neural networks, extreme event statistics, and electron transport. In this paper, a theoretical scheme for generating dynamical chaos in a Fabry–Perot cavity with two‐level atoms is investigated. Through the injection of atoms, controllable chaos of the cavity and mechanical oscillator is achieved simultaneously by the external laser field. The trajectory and the maximal Lyapunov exponent that characterize the properties of the chaos could be optimized by adjusting the coupling constant, driving field, injection of atoms, the frequency of the cavity, and the frequency of the mechanical oscillator. This study provides a new idea to manipulate the cavity and mechanical chaos assisted by two level atoms. It is hoped that the results presented can benefit controllable chaos generation and its applications. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of two two‐level atoms, which simultaneously couple to a quasi‐1D waveguide with rectangular cross section. The waveguide modes serve as environment, which induces the interaction and collective dissipation between the two distant atoms. When both of the two atoms are located in the middle of the waveguide, a retardation effect is observed, which can be broken by moving one of the atoms away from the center of the waveguide. To preserve the complete dissipation of the system via dark state mechanism, a scheme where the connection of the atoms is perpendicular to the axis of the waveguide is proposed. [ABSTRACT FROM AUTHOR]

Based on the principle of Fabry–Perot (F–P) cavity resonance and the selective permeability of gratings to specific electromagnetic waves, a graphene‐based metastructure (MS) is proposed for transmissive polarization conversion (PC). Using the full‐wave numerical simulation, it is found that by varying the Fermi energy of graphene, the effective resonance range of the suggested MS can be dynamically adjusted from 0.47 to 0.348–0.714 THz, achieving the target of precise to ultra‐broadband polarization modulation. In this paper, the plausibility of the structure is verified from multiple perspectives, and the correlation analyses of the electric and magnetic fields are the supporting illustrations. Additionally, the triggering mechanism of PC is visually illustrated in the study of the surface currents distributions. Simulation results reveal that the MS is superior in performance, functionality, and principle, and it is foreseen to hold excellent promise for integrated equipment in the terahertz (THz) band. [ABSTRACT FROM AUTHOR]

The near‐field effect of diffraction image self‐reproduction or self‐imaging of a periodic grating illuminated by quasi‐monochromatic wave is well‐known as the Talbot effect. Introducing a dislocation to a periodic structure provides a fork‐shaped modulation of the phase/amplitude, which produces discrete diffraction pattern in a far‐field consisting of optical vortices. In this paper, Fresnel diffraction at amplitude fork‐shaped grating is theoretically and experimentally studied. The coexistence of spatial ordering and local violation of translational symmetry of the structure manifests itself in a strict diffraction pattern consisting of optical vortices in the far‐field, which is shown to be accompanied by formation of a spatially ordered intensity distribution in the near‐field, reminiscent the Talbot carpets for periodic structures. These results demonstrate the first evidence of Talbot effect occurred under light diffraction at fork‐shaped gratings, being promising for deep understanding of near‐field singular optics phenomena. [ABSTRACT FROM AUTHOR]

In this paper, a Janus metastructure (JMS) is proposed that can act both as a logic gate and detect multiple physical quantities. By adjusting the incident angle of electromagnetic waves, arranging the dielectrics asymmetrically, and using the anisotropy of the plasma, the Janus function can be obtained, which gives the metastructure a multiscale property. Sharp transmission peak (TP) is generated by located defect mode resonance. The AND logic gate on the positive and negative scales can be realized by judging the TP value. By locking the point frequency of the TP, the refractive index, magnetic field strength, incident angle, and plasma density can be detected simultaneously on the two scales in the GHz range, which is rarely studied. Good sensing performances are also owned, and the corresponding optimal sensitivities are 0.095 (2πc/d)/RIU, 9.42 × 10−3 (2πc/d)/T, 1.48 × 10−3 (2πc/d)/°, and 0.035 (2πc/d) m3/1019, respectively. Compared with the traditional sensors, the proposed JMS equipped with two scales not only can realize the logic gate but also measure multiple physical quantities, which has a certain application potential. [ABSTRACT FROM AUTHOR]

In this paper, a protocol for nondestructive parity meter (NPM) of two cat‐state qubits is proposed. The physical model contains two cavities and an auxiliary qubit. For each cavity, the quantum information is encoded on the odd and even cat state, forming a cat‐state qubit. By adjusting the strength of the driving field on the auxiliary qubit, an effective Hamiltonian for cavity‐selective transition is derived. Moreover, reverse engineering based on the effective Hamiltonian is applied to find the evolution path, and the systematic‐error‐sensitivity nullification method is used to select proper parameters of the evolution path. In this way, robust control fields are designed to combat the influence of the systematic errors. Furthermore, the effects of random noise and decoherence on the fidelity of the protocol are considered. Numerical simulations show that the protocol is insensitive to the experimental imperfection, including systematic errors, random noise and decoherence. Therefore, the protocol is expected to expand the vision of realizing NPM. [ABSTRACT FROM AUTHOR]

Resonant scattering of electromagnetic (EM) waves by small particles is considered as one of the basic problems in metamaterial science. At present, special subwavelength resonators are considered as structural elements in chiral and bianisotropic metamaterials. There is a general consensus that these small scatterers behave like "artificial atoms" with strong electrical and magnetic responses and an interconnection between these responses. However, the observed effect of magnetoelectric (ME) coupling in these meta‐atoms is not associated with the near‐field manipulation properties caused by intrinsic magnetoelectricity. This arises the question whether ME point scatterers of EM radiation really exist. In this paper, we show that there are mesoscopic structures with electric and magnetic dipole‐carrying excitations that behave like point scatterers with their inherent magnetoelectricity. In such subwavelength resonators, coherent oscillations of the electric polarization and magnetization can be considered as quasistatic oscillations described by electrostatic (ES) and magnetostatic (MS) scalar wave functions. The ME resonance effect arises from the coupling of two, ES and MS, oscillations. The near fields of these resonators, called the ME near fields, are characterized by simultaneous violation of time reversal and inversion symmetry. In study of ME fields and EM problems associated with these fields, we put forward the concept of ME‐field electrodynamics. [ABSTRACT FROM AUTHOR]

In 1913, Albert Einstein and Michele Besso tried to explain the anomalous advance of Mercury's perihelion on the basis of the precursor theory of general relativity. A manuscript bundle documents their work. This manuscript was recently auctioned for a record amount. The paper gives a brief discussion of the significance and history of this manuscript. The anomalous advance of Mercury's perihelion is a classical test of general relativity. A manuscript by Albert Einstein and Michele Besso documenting their attempt in 1913 to explain the effect on the basis of a precursor theory was recently auctioned for a record amount. [ABSTRACT FROM AUTHOR]

Quantum‐information storage and retrieval in an optimized manner are of significance to information processing with composite systems. In this paper, an effective scheme is proposed for performing rapid information storage and retrieval between microwave photons and a nitrogen‐vacancy electron spin via shortcuts to adiabaticity. A qutrit of composite photon‐spin system interacts with two classical drivings. By modifying two original Rabi drivings, instead of directly adding an auxiliary counter‐diabatic interaction, information storage and retrieval can be rapidly performed with the optimized shortcut dynamics. Benefited from the shorter duration time, the shortcut‐based operation is more insensitive to decoherence effects than that of adiabatic counterpart. This strategy provides a promising avenue toward fast and robust information processing with solid‐state hybrid systems. [ABSTRACT FROM AUTHOR]

Today Noether's principal theorem occupies a prominent place in theoretical physics, though for a long time its significance was largely overlooked. Even now, relatively few physicists realize that Emmy Noether's original paper from 1918 contains two fundamental theorems. Moreover, both theorems are essential for understanding her original motivation, namely to distinguish between proper and improper conservation laws in physics. [ABSTRACT FROM AUTHOR]

This paper investigates the entanglement dynamics of a two‐qubit system in the presence of n‐sequential sin2$ \sin ^2$‐pulse shape. The study explores entanglement under two scenarios: when the system is completely isolated from the environment and when it interacts with one of the surrounding environments, namely the thermal environment and the common dephasing environment. The authors quantify entanglement through concurrence while systematically examining the effects of initial state preparation, qubit coupling strength, laser‐qubit interaction intensity, pulse sequences, and decohering environments. The results highlight that the entanglement of the two‐qubit system strongly depends on the initial state. Increasing the coupling strength between the qubits and the n‐sequential pulse enhances the maximum values of entanglement. Conversely, augmenting the laser‐qubits coupling or introducing the influence of the environment diminishes the entanglement. [ABSTRACT FROM AUTHOR]