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We apply the trajectory formulation to analyze the anomalous dynamics of cold atoms in an optical lattice. The phase space probability density function of cold atoms, their dynamics, and the mechanism of dynamic evolution from an initial Gaussian distribution to a power-law distribution are analyzed. The results of the trajectory formulation are in good agreement with the previously reported experimental results for the exponent of position variance for a long time and the position–momentum correlation. The self-similar natures of trajectories in phase space are found for Lévy distributions. Our results unify the raw moments that can be expressed as the summation of a number of independent, identically distributed variables and the anomalous dynamics, which holds promise for an intuitive interpretation anomalous behavior and their kinetic mechanisms from initial Gaussian to anomalous distributions for a long time. [ABSTRACT FROM AUTHOR]

We investigate the existence, stability and propagation dynamics of shock waves existing in defocusing saturable media modulated by a semi-infinite photonic lattice. Such surface waves consist of modulationally stable pedestals in bulk media and decaying oscillatory tails in semi-infinite photonic lattices. Due to Bragg-type reflection, they are strongly localized at the edge of the optical lattice. The kink steepness, pedestal height and localization degree can be controlled by propagation constant, saturable degree and lattice depth. Two types of kinks, i.e., "out-of-phase" and two branches of "in-phase" shock waves are revealed. Out-of-phase shock waves are stable in a substantial part of their existence domain. While the lower-branch in-phase waves with low energy flow are stable in almost their whole existence domain, the higher-branch in-phase waves are completely unstable. We thus show the first example of stable in-phase shock waves in nonlinear optics. Our findings provide new insight into the dynamics of semi-localized nonlinear surface shock waves or kink solitons. [ABSTRACT FROM AUTHOR]

As per bulk-edge correspondence, the junction between two topologically distinct lattices in a topological optical fiber supports topological interface states, which enable highly stable, scattering-free, robust propagation of light. We investigate the propagation characteristics of a multi-channel topological optical fiber having co-existing multiple topological interface states in the presence of potential structural defects and deformation in shape. The tolerance analysis has been carried out by deliberately introducing structural imperfections upto ⩽4% with reference to the annular area at the topological junction of trivial and non-trivial lattices. These studies demonstrate robust properties of multiple topological interface states despite the presence of such structural deformations. Furthermore, a deliberately introduced lateral misalignment upto a maximum of 800 nm of the topological junction exhibits a low splice loss of 0.3 dB and high confinement properties of the multiple topological interface states. These results clearly indicate that the propagation characteristics and properties of the co-existing multiple topological interface states exhibit exceptional tolerance to structural defects, junction deformations, and lateral misalignments, surpassing the performance of state-of-the-art conventional optical fibers. Hence, topological optical fibers could outperform conventional optical fibers in terms of undistorted signal transmission irrespective of fabrication-related potential structural defects. [ABSTRACT FROM AUTHOR]

We numerically study the optimal control of an atomic Bose-Einstein condensate in an optical lattice. We present two generalizations of the gradient-based algorithm, GRAPE, in the non-linear case and for a two-dimensional lattice. We show how to construct such algorithms from Pontryagin's maximum principle. A wide variety of target states can be achieved with high precision by varying only the laser phases setting the lattice position. We discuss the physical relevance of the different results and the future directions of this work. [ABSTRACT FROM AUTHOR]

High-resolution fluorescence imaging of ultracold atoms and molecules is paramount to performing quantum simulation and computation in optical lattices and tweezers. Imaging durations in these experiments typically range from a millisecond to a second, significantly limiting the cycle time. In this work, we present fast, 2.4 μs single-atom imaging in lattices, with 99.4% fidelity - pushing the readout duration of neutral atom quantum platforms to be close to that of superconducting qubit platforms. Additionally, we thoroughly study the performance of accordion lattices. We also demonstrate number-resolved imaging without parity projection, which will facilitate experiments such as the exploration of high-filling phases in the extended Bose-Hubbard models, multi-band or SU(N) Fermi-Hubbard models, and quantum link models. High-resolution imaging is essential for quantum simulation and computation in optical lattices and tweezers. Here, authors achieve fast 2.4-microsecond single-atom imaging with 99.4% fidelity and demonstrate number-resolved imaging without parity projection, advancing quantum readout capabilities. [ABSTRACT FROM AUTHOR]

With the aid of an optical frequency divider based on an optical frequency comb, the frequency of a laser at 431 nm is divided from a cavity-stabilized laser at 578 nm. Using the frequency-stabilized 431 nm laser, we observe a 2.5 kHz linewidth 4f146s2 1S0−4f135d6s2 (J = 2) transition of 171Yb atoms trapped in an optical lattice. By measuring the lattice-induced frequency shift, we determine the magic wavelength of the optical lattice for the 431 nm transition to be 797.97(20) nm. The frequency of the 431 nm transition is measured to be 695 171 054 856.9(1.1) kHz by referencing to the 1S0−3P0 transition at 578 nm of Yb atoms. [ABSTRACT FROM AUTHOR]

The wake evolution behind a moving impenetrable obstacle potential in a defective Bose–Einstein condensate (BEC) loaded in a shallow optical lattice is investigated. Exploiting the linear stability analysis method and potential flow theory, we analytically calculate the stability condition and velocity of Kármán vortex street, which agrees well with the numerical results. Based on it, the effects of defect on the stability of the Kármán vortex street and vortex pair shedding frequency are studied. The findings suggest that the stability of the vortex street deteriorates with the increase in lattice depth; however, special lattice constants can improve stability. It is worth noting that the shedding frequency of vortex pairs linearly increases with the obstacle velocity. Moreover, the relationship between critical velocity and vortex street structure parameters is established based on different expressions of shedding frequency, which may provide a new method for critical velocity measurement. Additionally, we also find that the Strouhal number (St) effectively characterizes the vortex street generation range when the impenetrable obstacle potential through BEC, which is significantly different from St ≈ 0.21 in classical fluids. [ABSTRACT FROM AUTHOR]

We demonstrate that fundamental nonlinear localized modes can exist in the Chen–Lee–Liu equation modified by several parity-time (P T) symmetric complex potentials. The explicit formula of analytical solitons is derived from the physically interesting Scarf-II potential, and families of spatial solitons in internal modes are numerically captured under the optical lattice potential. By the spectral analysis of linear stability, we observe that these bright solitons can remain stable across a broad scope of potential parameters, despite the breaking of the corresponding linear P T -symmetric phases. When these bright spatial solitons interact with external incident waves, they can always maintain their original shape, while the external incident wave may remain unchanged or may generate a reflected wave after the interaction. Then, the adiabatic switching of potential parameters is carried out in a way that allows these bright solitons to be excited from one unstable bound state to another alternative stable bound state. Many other intriguing properties associated with these nonlinear localized modes including the lateral power flow are further analyzed meticulously. Various high-order rogue waves induced by modulation instability in these P T -symmetric systems are generated too. These results may be useful to construct novel optical soliton communication schemes or design related optical materials. [ABSTRACT FROM AUTHOR]

In this work, a group theory-based formulation that introduces new classes of dihedral-symmetric beams is presented. Our framework leverages the algebraic properties of the dihedral group of rotations and reflections to transform input beams into closed-form families of dihedral-invariant wavefields, which will be referred to as dihedral beams. Each transformation is associated with a specific dihedral group in such a way that each family of dihedral beams exhibits the symmetries of its corresponding group. Our approach is inspired by one of the outcomes of this work: elegant Hermite–Gauss beams can be described as a dihedral interference pattern of elegant traveling waves, a new set of solutions to the paraxial equation also developed in this paper. Particularly, when taking elegant traveling waves as input beams, they transform into elegant dihedral beams possessing quasi-crystalline properties and including features like phase singularities, self-healing, and pseudo-nondiffracting propagation, as well as containing elegant Hermite and Laguerre–Gauss beams as special cases. Our approach can be applied to arbitrary scalar and vector input beams and constitutes a general group-theory formulation that can be extended beyond the dihedral group. [ABSTRACT FROM AUTHOR]

We study low-temperature properties of the four-component Fermi gas of neutral atoms in optical lattice for several cases of explicit breaking of the SU(4) pseudospin symmetry in the framework of the Fermi–Hubbard model. For a reduced two-site system, we analyze the energy states and effective magnetic couplings in cases, where four interacting spin flavors in the Hubbard Hamiltonian form the symmetry subgroups of the type "three by one" or "two by two" according to their tunneling and interaction amplitudes, independently, and study behavior of the corresponding effective Heisenberg models in the limit of strong interaction. We also obtain and analyze the spatial density distributions of spin components in a harmonic optical trap for each case of explicit symmetry breaking. [ABSTRACT FROM AUTHOR]

As an exceptional optical gene, the [PO4] tetrahedron is indispensable in the field of optical crystals due to its gain in the band gap of solid materials. However, the high symmetry of [PO4] tetrahedron hinders the achievement of large optical anisotropy in the lattice for phosphate crystal forms. In this work, the heteroleptic tetrahedra strategy, which involves replacing some of the oxygen atoms on regular oxy‐tetrahedra, is proven to be a feasible approach for preserving the wide transmission of the original [PO4] tetrahedra and improving the polarizability anisotropy. Based on this, eight methylphosphates are designed and synthesized for the phosphate system by substituting a [CH3] group for the O atom on the [PO4] tetrahedra. Theoretically, as compared to [PO4] units, [CH3PO3] and [CH3PO3H] units can improve the polarizability anisotropy, particularly [CH3PO3H] units, which have the potential to be birefringence‐active. The strong birefringence (exp. 0.108@546.1 nm) and short deep‐UV cutoff edge (195 nm) of nonmetallic methylphosphates [C(NH2)3][CH3PO3H] in the series suggest that it may be a possible short‐wave UV birefringent crystal. In addition to providing new birefringence‐active units for optical material design, this study validates the viability of modifying tetrahedra to improve inherent short board of nearly rigid [PO4] tetrahedra in phosphate family. [ABSTRACT FROM AUTHOR]

Quantum heat engines (QHEs) are established by applying the principles of quantum thermodynamics to small−scale systems, which leverage quantum effects to gain certain advantages. In this study, we investigate the quantum Otto cycle by employing the dipole−dipole coupled polar molecules as the working substance of QHE. Here, the molecules are considered to be trapped within an optical lattice and located in an external electric field. We analyze the work output and the efficiency of the quantum Otto heat engine (QOHE) as a function of various physical parameters, including electric field strength, dipole−dipole interaction and temperatures of heat baths. It is found that by adjusting these physical parameters the performance of the QOHE can be optimized effectively. Moreover, we also examine the influences of the entanglement and relative entropy of coherence for the polar molecules in thermal equilibrium states on the QOHE. Our results demonstrate the potential of polar molecules in achieving QHEs. [ABSTRACT FROM AUTHOR]

In photonic flat-band (FB) systems, which are characterized by a halting of light transmission, perturbations can play a major role in determining the transport properties of the system. In this work, this is exploited by purposefully including impurities in a photonic diamond chain with a constant synthetic flux per plaquette so that an effective system of choice can be tailored from the FB. By tuning both the separation between impurities and the flux value, any coupling distribution can be engineered. The effective system can also exhibit a nontrivial topology as we demonstrate by imprinting a Su–Schrieffer–Heeger model on the diamond chain, which is further shown to have enhanced robustness to disorder due to the extension of the impurity modes. Furthermore, effective non-Hermitian systems can also be realized by employing complex-valued impurities. We propose an implementation of the system in a lattice of optical waveguides carrying orbital angular momentum modes, where a phase in the coupling can be included and controlled geometrically. There, variations of the refractive index of chosen waveguides generate detunings that act as impurities, which couple together to form the effective system. This work opens the way for the design of topologically nontrivial models in other FB systems, or in other physical platforms. [ABSTRACT FROM AUTHOR]

In this paper, the magic wavelength of the 87Sr optical lattice clock is determined by a method that bypasses the need for lattice trap depth modulation. Instead, it relies on an additional AC Stark shift generated by a dipole beam operating near the frequency of the lattice light and oriented perpendicular to the optical lattice. The magic wavelength is inferred by measuring the AC Stark shift induced by the dipole beam as a function of its power under various frequency detunings. The effect of the dipole beam on the external states of the cold ensemble is evaluated through comparative analysis of the radial and axial sideband spectra, both with and without the dipole beam. Variations in density shift resulting from changes in external states are evaluated using comprehensive numerical calculations. By avoiding trap depth modulation, this method effectively suppresses the influence of the density shift, thereby offering a promising avenue for accurately determining the magic wavelength. [ABSTRACT FROM AUTHOR]

The effective control of atomic coherence with cold atoms has made atom interferometry an essential tool for quantum sensors and precision measurements. The performance of these interferometers is closely related to the operation of large wave packet separations. We present here a novel approach for atomic beam splitters based on the stroboscopic stabilization of quantum states in an accelerated optical lattice. The corresponding Floquet state is generated by optimal control protocols. In this way, we demonstrate an unprecedented Large Momentum Transfer (LMT) interferometer, with a momentum separation of 600 photon recoils (600 ℏk) between its two arms. Each LMT beam splitter is realized in a remarkably short time (2 ms) and is highly robust against the initial velocity dispersion of the wave packet and lattice depth fluctuations. Our study shows that Floquet engineering is a promising tool for exploring new frontiers in quantum physics at large scales, with applications in quantum sensing and testing fundamental physics. Large-scale atom interferometers enable precise measurements of fundamental constants and novel sensors. This study uses Floquet formalism to create an optimal transported state, resulting in an efficient large-momentum-transfer interferometer, advancing largescale interferometers. [ABSTRACT FROM AUTHOR]

Altermagnetism emerges as the third fundamental collinear magnetism recently. Associating nontrivial topology and quantum orders to this newly established magnetism is an important physical topic and may lead to interesting physics such as unusual quantum spin Hall effect with time-reversal-symmetry breaking, topological superconductivity and spin-valley locking. Here, we first generalize the spinless Haldane model from the usual honeycomb lattice to the otherwise simpler square lattice. We then restore the doublet spin degree of freedom, the resulted spinful model resembles the Kane-Mele model and is able to describe the unprecedented physics which intertwine C -paired spin-valley locking, Dirac physics, nontrivial band topology and altermagnetism. Our works shed lights on future studies and applications in spintronics and valleytronics for altermagnetic materials, the lattice theories developed in this article may also find their broad applications to optical lattice with ultra cold atoms, photonic lattice, etc. other than the usual electronic systems. [ABSTRACT FROM AUTHOR]

We examine the spectrum and quantum states of small lattices with cylindrical and toroidal topology subject to a scalar gauge potential that introduces a position dependent phase in the inter-site coupling. Equivalency of gauges assumed in infinite lattices is generally lost due to the periodic boundary conditions, and conditions that restore it are identified. We trace the impact of various system parameters including gauge choice, boundary conditions and inter-site coupling strengths, and an additional axial field. We find gauge dependent appearance of avoided crossings and persistent degeneracies, and we show their impact on the associated eigenstates. Smaller lattices develop prominent gaps in spectral lines associated with edge states, which are suppressed in the thermodynamic limit. Toroidal lattices have counterparts of most of the features observed in cylindrical lattices, but notably they display a transition from localization to delocalization determined by the relation between the field parameter and the number of lattice sites. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the quantum phases of two-component bosons in a non-Hermitian optical lattice system featuring a nonreciprocal hopping phase factor. Our analysis focuses on the Bose–Hubbard model in a two-dimensional (2D) square lattice, utilizing the inhomogeneous dynamical Gutzwiller mean-field theory (DGMFT) to examine the ground state. The impact on quantum phases of the inter component interaction varies in the weak-interaction (the inter-component interactions are smaller than intra-component interactions, i.e., | U a b | ≤ U) and in the strong-interaction (the inter-component interactions are bigger than intra-component interactions, i.e., U a b > U) regime. In the weak regime, we observe a diverse range of quantum phases, including vortex-like liquid, MI islands (the Mott insulator (MI) islands periodically distributed in the superfluid (SF) background) and SF islands (the SF islands periodically distributed in the MI background), and the inter-component counterflow superfluid (CFSF) phases. In the strong regime, we observe phase separation of the two-component bosons. [ABSTRACT FROM AUTHOR]

Density–density correlation analysis is a convenient diagnostic tool to reveal the hidden order in the strongly correlated phases of ultracold atoms. We report on a study of the density–density correlations of ultracold bosonic atoms which were initially prepared in a Mott insulator (MI) state in one-dimensional optical lattices. For the atomic gases released from the deep optical lattice, we extracted the normalized density–density correlation function from the atomic density distributions of freely expanded atomic clouds. Periodic bunching peaks were observed in the density–density correlation spectra, as in the case of higher-dimensional lattices. Treating the bosonic gas within each lattice well as a subcondensate without quantum tunneling, we simulated the post-expansion density distribution along the direction of the 1D lattice, and the calculated density–density correlation spectra agreed with our experimental observations. [ABSTRACT FROM AUTHOR]

In this paper, we employ the auxiliary equation method (AEM) to show the leverage of the nearest neighbors hopping and the boson–boson interaction in a zig zag optical lattice on the stressed optical solitons (os) and the Modulation Instability (MI) gain of cold bosonic atoms. The pedestal of the work is set on the continuum approximation of a cold bosonic atoms in a zig zag optical lattice which has demonstrated in detailed in refs. [Tala-Tebue E, Rezazadeh H, Djoufack ZI, et al. Optical solutions of cold bosonic atoms in a zig–zag optical lattice. Opt Quant Electron 53(2021):44; Djoufack ZI, TalaTebue E, FotsaNgafo F, et al. Quantum breathers associated with modulational instability in 1D ultracold boson in optical lattices involving nextnearest neighbor interactions. Optik 164(2018):575–589]. The results collected have enclosed bright, dark optical solitons and the combined bright-dark and bright-bright optical solitons. Compared the acquired results with Tala-Tebue et al. [Optical solutions of cold bosonic atoms in a zig–zag optical lattice. Opt Quant Electron 53(2021):44], further the os including U-shaped and W-shaped profile have been drop in and the powerful of the nearest neighbors hopping and the boson–boson interaction has been exposed across the spatiotemporal and plot evolution of the bright and dark os. Therewith, the MI bands have been stressed and it is observed some new attitude of the MI gain spectra under the induction of the model parameters. The collected results are new in literature in our knowledge and will improve the previous results acquired in refs. [Tala-Tebue E, Rezazadeh H, Djoufack ZI, et al. Optical solutions of cold bosonic atoms in a zig–zag optical lattice. Opt Quant Electron 53(2021):44; Djoufack ZI, TalaTebue E, FotsaNgafo F, et al. Quantum breathers associated with modulational instability in 1D ultracold boson in optical lattices involving nextnearest neighbor interactions. Optik 164(2018):575–589; Zhao XH, Tian B, Liu DY, et al. Dark solitons interaction for a (2+1)-dimensional nonlinear Schrödinger equation in the Heisenberg ferromagnetic spin chain. Superlattices Microstruct 100(2016):587–595; Uddin MF, Hafez MG, Hammouch Z, et al. Periodic and rogue waves for Heisenberg models of ferromagnetic spin chains with fractional beta derivative evolution and obliqueness. Waves Random Complex Media 2020. https://doi.org/10.1080/17455030.2020.1722331; Inc M, Aliyu AI, Yusuf A. Optical solitons to the nonlinear Shrdingers equation with spatio-temporal dispersion using complex amplitude ansatz. J Mod Opt 2017;64(21):2273–2280]. [ABSTRACT FROM AUTHOR]

This work delves into the behavior of cold bosonic atoms within a zigzag optical lattice which offers a rich platform for studying quantum many‐body physics and has potential applications in various fields including quantum simulation, quantum computing, and precision measurement. The study aims to derive exact solutions and explore qualitative properties through dynamical analysis. Exact solutions of the nonlinear differential equation model can provide insights into the behavior of bosonic atoms in complex optical lattice configurations, allowing researchers to simulate and study phenomena such as quantum phase transitions, many‐body localization, and exotic states of matter. The invariant analysis has been performed for the first time on the specified equation, yielding a reduced system of equations with forms that are easier to handle. Novel techniques are applied to extract solutions from the reduced system of equations obtained via invariant analysis. The results reveal a rich set of solutions, including various traveling wave solutions and doubly periodic functions in the form of Jacobian elliptic functions. Bifurcation analysis, conducted through phase portraits, provides insights into the system's long‐term behavior under different parameter values. This work contributes to a deeper understanding of the dynamics of cold bosonic atoms in optical lattices via 2D and 3D plots of obtained solutions depicting the change in the behavior of soliton solutions with fractional derivative parameter. [ABSTRACT FROM AUTHOR]

Atoms confined in the optical lattice can be interrogated with Doppler- and recoil-free operation. However, if not properly controlled, the optical lattice may limit clock accuracy. To improve the lattice-light-shift uncertainty, the cooling and trapping lasers' frequency stability is optimized, and the atom's signal stability is enhanced. A ring-cavity Ti:sapphire laser is locked to the optical frequency comb, which is referenced to a 578 nm ultra-stable laser, and the beat note's stability is on the order of 10−16. Using a 10 cm Fabry–Pérot cavity referenced to the Ti:sapphire laser, the optical frequency stability is transferred to the 399 nm cooling laser, creating favorable conditions for evaluating the lattice-light-shift accurately. We reevaluate lattice-light-shift in our 171Yb optical lattice clock with an uncertainty of 8.1 × 10−18, which is an order lower than our previous result, and the magic frequency is determined to be 394 798 266.6(1.3) MHz. [ABSTRACT FROM AUTHOR]

This paper describes how moiré plasmonic nanoparticle lattices can exhibit lasing action over a broad wavelength and wavevector range. Moiré nanolithography is combined with the PEEL (Photolithography, Etching, Electron‐beam deposition, and Lift‐off) process to fabricate in‐plane incommensurate lattices with optical properties beyond the restricted geometries of Bravais lattices. Because of increased rotational symmetry, moiré lattices support a larger number of transverse electric and transverse magnetic modes relative to their periodic base lattices. It is found that multidirectional lasing characteristics can be predicted by the symmetry of the moiré reciprocal lattice. Incommensurate moiré plasmonic lattices combine advantages of the dense band structures observed in aperiodic lattices with that of predicted modes in Bravais lattices for light‐based technologies in coherent light sources and multiplexed data transfer. [ABSTRACT FROM AUTHOR]

Optical vortex lattices (OVLs) with diverse modes show potential for a wide range of applications, such as high-capacity optical communications, optical tweezers, and optical measurements. However, vortices in typical regulated OVLs often exhibit irregular shapes, such as being narrow and elongated. The resulting increase in asymmetry negatively impacts the efficiency of particle trapping. Additionally, the vortex radii expand with an increase in topological charge (TC), limiting the TC value of the vortices and hindering their ability to fully utilize orbital angular momentum (OAM). Herein, we propose an alternative approach to custom OVLs using off-axis techniques combined with amplitude modulation. Amplitude modulation enables the precise generation of an OVL with perfect vortex properties, known as a perfect off-axis OVL. Further, the number of vortices in the perfect off-axis OVL, the off-axis distances, and the TC can be freely modulated while maintaining a circular mode. This unique OVL will promote new applications, such as the complex manipulation of multi-particle systems and optical communication based on OAM. [ABSTRACT FROM AUTHOR]

Ultracold quantum gases are usually prepared in conservative traps for quantum simulation experiments. The atomic density inhomogeneity, together with the consequent position-dependent energy and time scales of cold atoms in traditional harmonic traps, makes it difficult to manipulate and detect the sample at a higher level. These problems are partially solved by optical box traps made of blue-detuned hollow beams. However, generating a high-quality hollow beam with high light efficiency for the box trap is challenging. Here, we present a scheme that combines the fixed optics, including axicons and prisms, to pre-shape a Gaussian beam into a hollow beam with a digital micromirror device (DMD) to improve the quality of the hollow beam further, providing a nearly ideal optical potential of various shapes for preparing highly homogeneous cold atoms. The highest power-law exponent of potential walls can reach a value over 100, and the light efficiency from a Gaussian to a hollow beam is also improved compared to direct optical shaping by a mask or a DMD. Combined with a one-dimensional optical lattice, a nearly ideal two-dimensional uniform quantum gas with different geometrical boundaries can be prepared for exploring quantum many-body physics to an unprecedented level. [ABSTRACT FROM AUTHOR]

As we know, valley-Hall kink states or pseudospin helical edge states are excited by polarized-momentum-locking [left-handed circular polarization (LCP) and right-handed circular polarization (RCP)] because the valley-Hall kink modes or pseudospin polarized modes have intrinsic and local chirality, which is difficult for these states to achieve phase modulation. Here we theoretically design and study a compatible topological photonic system with coexistence of photonic quantum Hall phase and pseudospin Hall phase, which is composed of gyromagnetic photonic crystals with a deformed honeycomb lattice containing six cylinders. A typical kind of hybrid topological waveguide states with pseudospin-characteristic, magnetic field-dependent, and strong robustness against backscattering and perfect electric conductor (PEC) is realized in the present system. Furthermore, we re-design a structure with intersection-liked, achieve splitting for one-way pseudospin quantum Hall edge states by using phase modulation. Robustness of the one-way pseudospin-quantum Hall edge states in splitting has been demonstrated as well. Additionally, PEC inserted in transport channel brings optical path difference in waveguide transmission, which would influence splitting for hybrid topological waveguide states in phase difference modulation. This work not only provides a new way for manipulation (i.e., phase modulation) of hybrid topological waveguide states in compatible topological photonic system from distinct topological classes but also has potential in various applications, such as sensing, signal processing, and on-chip communications. [ABSTRACT FROM AUTHOR]

The optical response of a layered anisotropic crystal Nb2SiTe4 was investigated under varying pressure using synchrotron infrared spectroscopy, Raman spectroscopy, and first-principles calculation. This study revealed diverse trends in optical response and bandgap at different pressure levels. Below 5 GPa, the bandgap decreases rapidly due to the reduction of interlayer distance. The Raman and infrared optical response show significant changes at 11 and 21 GPa, suggesting structural and electronic structure transformation at these pressure points. Meanwhile, the optical responses exhibited distinct pressure effects along different crystal axes. Overall, these results provide valuable insights into the pressure-induced lattice deformation and optical transitions in Nb2SiTe4 and similar layered anisotropic materials, contributing to an insightful understanding of layered materials under pressure. [ABSTRACT FROM AUTHOR]

Quantum optimal control (QOC) is a set of methods for designing time-varying electromagnetic fields to perform operations in quantum technologies. This tutorial paper introduces the basic elements of this theory based on the Pontryagin maximum principle, in a physicist-friendly way. An analogy with classical Lagrangian and Hamiltonian mechanics is proposed to present the main results used in this field. Emphasis is placed on the different numerical algorithms to solve a QOC problem. Several examples ranging from the control of two-level quantum systems to that of Bose–Einstein condensates (BECs) in a one-dimensional optical lattice are studied in detail, using both analytical and numerical methods. Codes based on shooting method and gradient-based algorithms are provided. The connection between optimal processes and the quantum speed limit is also discussed in two-level quantum systems. In the case of BEC, the experimental implementation of optimal control protocols is described, both for two-level and many-level cases, with the current constraints and limitations of such platforms. This presentation is illustrated by the corresponding experimental results. [ABSTRACT FROM AUTHOR]

A non-unitary transformation leading to a Hatano–Nelson problem is performed on an array of equally-spaced optical waveguides. Such transformation produces a non-reciprocal system of waveguides, as the corresponding Hamiltonian becomes non-Hermitian. This may be achieved by judiciously choosing an attenuation (amplification) of the injected (or exciting) field. The non-Hermitian transport induced by such transformation is studied for several cases and closed analytical solutions, not present in the available literature, are straightforwardly obtained. The corresponding non-Hermitian Hamiltonian may represent an open system that interacts with the environment, either loosing to or being provided with energy from the exterior. [ABSTRACT FROM AUTHOR]

This work develops a quantum control application of many-body quantum chaos for ultracold bosonic gases trapped in optical lattices. It is long known how to harness exponential sensitivity to changes in initial conditions for control purposes in classically chaotic systems. In the technique known as targeting, instead of a hindrance to control, the instability becomes a resource. Recently, this classical targeting has been generalized to quantum systems either by periodically countering the inevitable quantum state spreading or by introducing a control Hamiltonian, where both enable localized states to be guided along special chaotic trajectories toward any of a broad variety of desired target states. Only strictly unitary dynamics are involved; i.e. it gives a coherent quantum targeting. In this paper, the introduction of a control Hamiltonian is applied to Bose–Hubbard systems in chaotic dynamical regimes. Properly selected unstable mean field solutions can be followed particularly rapidly to states possessing precise phase relationships and occupancies. In essence, the method generates a quantum simulation technique that can access rather special states. The protocol reduces to a time-dependent control of the chemical potentials, opening up the possibility for application in optical lattice experiments. Explicit applications to custom state preparation and stabilization of quantum many-body scars are presented in one- and two-dimensional lattices (three-dimensional applications are similarly possible). [ABSTRACT FROM AUTHOR]

We consider the ground state of Rydberg-dressed Bose gas with spin–orbit coupling and confined in a two-dimensional optical lattice. The effects of system's parameters, especially the nonlocal Rydberg interaction and spin–orbit coupling, on the ground-state structure of such a system are explored in full parameter space. It is found that in the absence of spin–orbit coupling, the ground-state structure of the system changes from the initial optical lattice structure to a two-dimensional periodic one with the cell size decreasing with the strength of Rydberg interaction. In the presence of spin–orbit coupling, both the phase and the internal structure of unit cell show strong dependence on the strength of spin–orbit coupling. Finally, the strong interacting gas is also considered. [ABSTRACT FROM AUTHOR]

The chiral light field has attracted great attention owing to its interaction with chiral matter. The generation of chiral light fields with rich structures has become crucial as it can expand application scenarios. Herein, we introduce a chiral optical vortex lattice. As a whole, the optical vortex lattice has a chiral intensity distribution, with each spiral arm having sub-vortices (chiral phase). By using an expansion factor to adjust the involute of a circular lattice, this helical optical vortex lattice can be continuously varied from a circular lattice. The chirality of intensity and phase can be controlled independently. Furthermore, the optical tweezers using the lattice demonstrate the capability of sub-vortices to manipulate particle movement, with the chiral intensity determining the trajectory of particle motion. As the lattice possesses both intensity and phase chirality, it may also find potential applications in tasks such as chiral structure microfabrication. [ABSTRACT FROM AUTHOR]

Most recently, the path integral molecular dynamics has been successfully used to consider the thermodynamics of single-component identical bosons and fermions. In this work, the path integral molecular dynamics is developed to simulate thermodynamics, Green's function, and momentum distribution of two-component bosons in three dimensions. As an example of our general method, we consider the thermodynamics of up to 16 bosons in a three-dimensional harmonic trap. For noninteracting spinor bosons, our simulation shows a bump in the heat capacity. As the repulsive interaction strength increases, however, we find the gradual disappearance of the bump in the heat capacity. We believe that this simulation result can be tested by ultracold spinor bosons with optical lattices and magnetic-field Feshbach resonance to tune the inter-particle interaction. We also calculate Green's function and momentum distribution of spinor bosons. Our work facilitates the exact numerical simulation of spinor bosons, whose property is one of the major problems in ultracold Bose gases. [ABSTRACT FROM AUTHOR]

Nonlinear feedback between the gauge field and the material field can yield novel quantum phenomena. Here, the interplay between a density-dependent artificial gauge field and Bose–Einstein condensates (BECs) trapped in an optical lattice is studied. The energy spectrum and superfluidity represented by energetic and dynamical stabilities of the system are systematically discussed. A density-dependent artificial gauge field with a back-action between the BECs dynamics and the gauge field induces an effective atomic interaction that depends on the quasi-momentum and density of the condensates, resulting in a symmetry-broken energy spectrum and exotic stability phase diagram, that is, the system is only stable in a certain range of atoms density and under a limited lattice strength. The density-dependent artificial gauge field changes the sequence for the emergence of energetic and dynamical instability and the regimes of the energetic and dynamical instabilities are significantly separated, offering an efficient way to examine the energetic and dynamical instabilities of superfluids separately. In particular, the density-dependent artificial gauge field, as a mechanism for transferring momentum to the fluid, results in dynamic instability of the condensates even in free space. Our results provide deep insights into the dynamical response of superfluid systems to gauge fields and have potential applications for the coherent control of exotic superfluid states. [ABSTRACT FROM AUTHOR]

Artificial 1D and 2D lattices have emerged as a powerful platform for the emulation of lattice Hamiltonians, the fundamental study of collective many‐body effects, and phenomena arising from non‐trivial topology. Exciton‐polaritons, bosonic part‐light and part‐matter quasiparticles, combine pronounced nonlinearities with the possibility of on‐chip implementation. In this context, organic semiconductors embedded in microcavities have proven to be versatile candidates to study nonlinear many‐body physics and bosonic condensation, and in contrast to most inorganic systems, they allow the use at ambient conditions since they host ultra‐stable Frenkel excitons. A well‐controlled, high‐quality optical lattice is implemented that accommodates light‐matter quasiparticles. The realized polariton graphene presents with excellent cavity quality factors, showing distinct signatures of Dirac cone and flatband dispersions as well as polariton lasing at room temperature. This is realized by filling coupled dielectric microcavities with the fluorescent protein mCherry. The emergence of a coherent polariton condensate at ambient conditions are demonstrated, taking advantage of coupling conditions as precise and controllable as in state‐of‐the‐art inorganic semiconductor‐based systems, without the limitations of e.g. lattice matching in epitaxial growth. This progress allows straightforward extension to more complex systems, such as the study of topological phenomena in 2D lattices including topological lasers and non‐Hermitian optics. [ABSTRACT FROM AUTHOR]

A surface chemical reaction network (sCRN, Qian and Winfree in DNA Computing and Molecular Programming: 20th International Conference, DNA 20, Kyoto, Japan, September 22–26, 2014. Proceedings 20. Springer, 2014) is an emergent paradigm for molecular programming, in which a chemical molecule is placed at each site of a lattice, and each molecule may undergo either bi-molecular reactions associated with one of the nearest molecules or uni-molecular reactions autonomously. The lattice structure as well as the localized reactions between molecules facilitate an effective formalization of sCRNs in the framework of cellular automata. This formalism not only allows a systematic evaluation of the complexity of a sCRN, but also enables a formal approach to reduce the model's complexity for the sake of improving its effectiveness. To this end, this paper proposes a new sCRN model that has less complexity measured in terms of the numbers of both cell states and transition rules. Especially, universality of computations will be shown by implementing all asynchronous circuits, including the well-known full-adder, into the sCRN. The decreased complexity may enhance the feasibility of the proposed sCRN model for physical implementation. [ABSTRACT FROM AUTHOR]

Based on the extended Huygens–Fresnel integral, the analytical expressions for the average intensity of a partially coherent radially polarized rotating elliptical cosine-Gaussian optical lattice (PCRPREGOL) in the anisotropic turbulence are derived. We find that the lattice intensity profile and the spatial degree of coherence will display periodicity reciprocity over a long propagation distance even though the lattices are affected by the turbulence. The periodicity reciprocity of PCRPREGOL is not only affected by the lattice parameter but also affected by the beam order factor. The intensity pattern of the PCRPREGOL in a certain distance can be modulated by the lattice lobes, and some interesting phenomena appear due to the overlap of four lattice arrays during the evolution of the PCRPREGOL. At the same time, the four periodic grid patterns and the tapered light intensity composed by four parts of the PCRPREGOL can be flexibly tuned by modulating the source correlation parameters and the lattice constant. Last but not least, we also discuss the coherent and polarized characteristics of the PCRPREGOL in the anisotropic turbulence. [ABSTRACT FROM AUTHOR]

Spatially overlapped coupled matter‐wave bright solitons are considered in binary Bose‐Einstein condensates with nonlinear optical lattices(NOLs) and study the properties of scattering patterns due to a localized defect. It is shown that spatially overlapped solitons become separated and exhibit different scattering patterns with the variation of inter‐species interaction. The NOL interplays with the defect and tends to influence the scattering properties. However, the effect of NOL varies with strength of inter‐component interaction. It is found that, if this interaction is weak then the scattering center gets shifted outside the defect. However, for a stronger inter‐component interaction, the scattering takes place from the defect and leads to different scattering patterns. [ABSTRACT FROM AUTHOR]

The electronic properties of calcium-intercalated graphite (CaC6) as a function of pressure are revisited using density functional theory (DFT). The electronic band structures of CaC6, like many other layered superconducting materials, display cosine-shaped bands at or near the Fermi level (FL). Such bands encompass bonding/antibonding information with a strong connection to superconducting properties. Using a hexagonal cell representation for CaC6, the construction of a double supercell in the c-direction effects six-folding in the reciprocal space of the full cosine function, explicitly revealing the bonding/antibonding relationship divide at the cosine midpoint. Similarly, folding of the Fermi surface (FS) reveals physical phenomena relevant to electronic topological transitions (ETTs) with the application of pressure. The ETT is characterised by a transition of open FS loops to closed loops as a function of pressure. As the highest transition temperature is reached with pressure, the dominant continuous, open FS loops shift to a different region of the FS. For CaC6, the peak value for the superconducting transition temperature, Tc, occurs at about 7.5 GPa, near the observed pressure of the calculated ETT. At this pressure, the radius of the nearly spherical Ca 4s-orbital FS coincides with three times the distance from the Γ centre point to the Brillouin zone (BZ) boundary of the 2c supercell. In addition, the ETT coincides with the alignment of the nonbonding (inflection) point of the cosine band with the FL. At other calculated pressure conditions, the Ca 4s-orbital FS undergoes topological changes that correspond and can be correlated with experimentally determined changes in Tc. The ETT is a key mechanism that circumscribes the known significant drop in Tc for CaC6 as a function of increasing pressure. Consistent calculated responses of the ETT to pressure match experimental measurements and validate the examination of superlattices as important criteria for understanding mechanisms driving superconductivity. [ABSTRACT FROM AUTHOR]

Disorder-induced heating (DIH) prevents ultracold neutral plasma into the electron strong coupling regime. Here, we propose a scheme to suppress electronic DIH via optical lattice. We simulate the evolution dynamics of ultracold neutral plasma constrained by three-dimensional optical lattice using the classical molecular dynamics method. The results show that for experimentally achievable conditions, electronic DIH is suppressed by a factor of 1.3, and the Coulomb coupling strength can reach 0.8, which is approaching the strong coupling regime. Suppressing electronic DIH via optical lattice may pave a way for the research of electronic strongly coupled plasma. [ABSTRACT FROM AUTHOR]

The experimental comparison of two thulium optical lattice clocks in a time interval of up to one hour has been carried out. The synchronous comparison of a clock transition in two independent atomic ensembles using a single ultrastable laser has allowed us to eliminate fluctuations of the laser frequency from the measured frequency difference and to reach a relative measurement error of 10–16 after 500-s averaging, which corresponds to a relative instability of . The successful demonstration of the long-term operation of two systems using the synchronous comparison of clock transitions opens the possibility of studying systematic shifts in thulium optical clocks with an uncertainty of 10–17. [ABSTRACT FROM AUTHOR]

Diffractive plasmonic metasurfaces offer the possibility of controlling the flow of light in flat optical systems through the excitation of lattice plasmon modes by a careful metasurface design. Nonetheless, a remaining challenge for this type of structure is the dynamic control of its optical properties via degrees of freedom, such as the polarization states of incoming light. In this report, we explain theoretically and demonstrate experimentally the polarization control over amplitude and propagation direction of lattice plasmon modes supported by a multipolar plasmonic metasurface. These unidirectional optical waves result from the coupling between near-field effects of individual meta-atoms and far-field effects originating from the lattice modes. The device operates over a broad wavelength range, maintaining its directional behavior and enabling it to operate also as a polarization-controlled directional diffraction grating, a power splitter, or an optical router for on-chip photonics applications. [ABSTRACT FROM AUTHOR]

Based on the two-dimensional (2D) nonlinear Schrödinger equation, we investigate the collapse dynamics of a vector vortex optical field (VVOF) in nonlinear Kerr media with parity–time (PT)-symmetric modulation. The critical power for the collapse of a VVOF in a Kerr-ROLP medium (Kerr medium with a real optical lattice potential) is derived. Numerical simulations indicate that the number, position, propagation distance, and collapse profile of the collapse of a VVOF in sine and cosine parity–time-symmetric potential (SCPT) Kerr media are closely related to the modulation depth, initial powers, and the topological charge number of a VVOF. The VVOF collapses into symmetric shapes during propagation in a Kerr-ROLP medium, and collapse shapes are sensitively related to the density of the PT-symmetric optical lattice potential. In addition, due to gain–loss, the VVOF will be distorted during propagation in the Kerr-SCPT medium, forming an asymmetric shape of collapse. The power evolution of the VVOF in a Kerr-SCPT medium as a function of the transmission distance with different modulating parameters and topological numbers is analyzed in detail. The introduction of PT-symmetric optical lattice potentials into nonlinear Kerr materials may provide a new approach to manipulate the collapse of the VVOF. [ABSTRACT FROM AUTHOR]

Extreme wave events or rogue waves (RWs) are both statistically rare and of exceptionally large amplitude. They are observed in many complex systems ranging from oceanic and optical environments to financial models and Bose–Einstein condensates. As they appear from nowhere and disappear without a trace, their emergence is unpredictable and non‐repetitive, which makes them particularly challenging to control. Here, the use of genetic algorithms (GAs), which are exclusively designed for searching and optimizing stationary or repetitive processes in nonlinear optical systems, is extended to the active control of extreme events in a fiber laser cavity. Feeding real‐time spectral measurements into a GA controlling the electronics to optimize the cavity parameters, the wave events are able to be triggered in the cavity that have the typical statistics of RWs in the frequency domain. The intensity of the induced RWs can also be tailored. This accurate control enables the generation of optical RWs with a spectral peak intensity 32.8 times higher than the significant intensity threshold. A rationale is proposed and confirmed by numerical simulations of the laser model for the related frequency up‐ and downshifting of the optical spectrum that are experimentally observed. [ABSTRACT FROM AUTHOR]

High-quality lattice resonances in arrays of infrared antennas operating in an open-cavity regime form polariton states by means of strong coupling to molecular vibrations. We studied polaritons formed by carbonyl stretching modes of (poly)methyl methacrylate on resonant antenna arrays using femtosecond 2DIR spectroscopy. At a normal incidence of excitation light, doubly degenerate antenna-lattice resonances (ALRs) form two polariton states: a lower polariton and an upper polariton. At an off-normal incidence geometry of 2DIR experiments, the ALR degeneracy is lifted and, consequently, the polariton energies are split. We spectrally resolved and tracked the time-dependent evolution of a cross-peak signal associated with the excitation of reservoir states and the unidirectional transfer of the excess energy to lower polaritons. Bi-exponential decay of the cross-peak suggests that a reversible energy exchange between the bright and dark lower polaritons occurs with a characteristic transfer time of ∼200 fs. The cross-peak signal further decays within ∼800 fs, which is consistent with the relaxation time of the carbonyl stretching vibration and with the dephasing time of the ALR. An increase in the excitation pulse intensity leads to saturation of the cross-peak amplitude and a modification of the relaxation dynamics. Using quantum-mechanical modeling, we found that the kinetic scheme that captures all the experimental observations implies that only the bright lower polariton accepts the energy from the reservoir, suggesting that transfer occurs via a mechanism involving dipole–dipole interaction. An efficient reservoir-to-polariton transfer can play an important role in developing novel room-temperature quantum optical devices in the mid-infrared wavelength region. [ABSTRACT FROM AUTHOR]

In pursuit of designing superior type-II superlattice barrier infrared detectors, this study encompasses an exhaustive analysis of utilizing M-structured superlattices for both the absorber and barrier layers through proper band engineering and discusses its potential benefits over other candidates. The electronic band properties of ideally infinite M-structures are calculated using the eight band k. p method that takes into account the effects of both strain and microscopic interface asymmetry to primarily estimate the bandgap and density-of-states effective mass and their variation with respect to the thicknesses of the constituent material layers. In contrast, for practical finite-period structures, the local density-of-states and spectral tunneling transmission and current calculated using the Keldysh non-equilibrium Green's function approach with the inclusion of non-coherent scattering processes offer deep insights into the qualitative aspects of miniband and localization engineering via structural variation. Our key results demonstrate how to achieve a wide infrared spectral range, reduce tunneling dark currents, induce strong interband wavefunction overlaps at the interfaces for adequate absorption, and excellent band-tunability to facilitate unipolar or bipolar current blocking barriers. This study, therefore, perfectly exemplifies the utilization of 6.1 Å material library to its full potential through the demonstration of band engineering in M-structured superlattices and sets up the right platform to possibly replace other complex superlattice systems for targeted applications. [ABSTRACT FROM AUTHOR]

We propose a compact computational method based on the capacitance model for the efficient design of graphene-based synaptic field effect transistors (FETs), in which the hysteresis of conduction characteristics due to the channel–gate interface trap is used as synaptic plasticity. Using our method to calculate the conduction properties of graphene and armchair graphene nanoribbon (AGNR) superlattice FETs, it is shown that the AGNR can achieve an efficient conductance change rate Δ w , which is approximately 7.4 times that of graphene. It was also found that Δ w was the greatest when the gate oxide thickness was around 2–3 nm, which is near the limit of miniaturization. These results suggest that the proposed synaptic FETs are a promising approach to realize large scale integration chips for biological timescale computation. [ABSTRACT FROM AUTHOR]