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Quantum phase transition modulation in an atomtronic Mott switch
摘要： Mott insulators provide stable quantum states and long coherence times due to small number fluctuations, making them good candidates for quantum memory and atomic circuits. We propose a proof-of-principle for a 1D Mott switch using an ultracold Bose gas and optical lattice. With time-evolving block decimation simulations—efficient matrix product state methods—we design a means for transient parameter characterization via a local excitation for ease of engineering into more complex atomtronics. We perform the switch operation by tuning the intensity of the optical lattice, and thus the interaction strength through a conductance transition due to the confined modifications of the 'wedding cake' Mott structure. We demonstrate the time-dependence of Fock state transmission and fidelity of the excitation as a means of tuning up the device in a double well and as a measure of noise performance. Two-point correlations via the g(2) measure provide additional information regarding superfluid fragments on the Mott insulating background due to the confinement of the potential.
关键词： quantum gas,atomtronic switch,optical lattice,atomtronics,quantum phase transition,matrix product states,Mott insulator
更新于2025-09-23 15:23:52
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orbitals in two-dimensional regular optical lattices
摘要： In solids, crystal field splitting refers to the lifting of atomic orbital degeneracy by the surrounding ions through the static electric field. Similarly, we show that the degenerated d orbitals, which were derived in the harmonic oscillator approximation, are split into a low-lying dx2+y2 singlet and a dx2?y2/xy doublet by the high-order Taylor polynomials of triangular optical potential. The low-energy effective theory of the orbital Mott insulator at 2/3 filling is generically described by the Heisenberg-compass model, where the antiferro-orbital exchange interactions of compass type depend on the bond orientation and are geometrically frustrated in the triangular lattice. While, for the square optical lattice, the degenerated d orbitals are split into a different multiplet structure, i.e., a low-lying dx2±y2 doublet and a dxy singlet, which has its physical origin in the C4v point group symmetry of square optical potential. Our results build a bridge between ultracold atom systems and solid-state systems for the investigation of d-orbital physics.
关键词： orbital Mott insulator,Heisenberg-compass model,crystalline splitting,d orbitals,optical lattices
更新于2025-09-23 15:21:21
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Quantum control with measurements and quantum Zeno dynamics
摘要： We introduce an efficient iterative method to prepare a target state in Hilbert spaces with high dimensionality using a combination of unitary evolution, measurements, and quantum Zeno dynamics. The latter confines the evolution within Zeno subspaces of decreasing size. This gives an exponential speedup relative to the case of states evolving in the full Hilbert space between projective measurements. We demonstrate our approach on the control problem of rapidly transferring a superfluid into the Mott insulator in the Bose-Hubbard model. We discuss the general applicability of the method by preparing arbitrary superpositions with random Hamiltonians.
关键词： quantum Zeno dynamics,quantum control,Mott insulator,Bose-Hubbard model,measurements
更新于2025-09-23 15:19:57
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Performance Investigation of Mott-Insulator LaVO3 as a Photovoltaic Absorber Material
摘要： Mott insulators have recently been identi?ed as potential solar energy conversion material due to their favorable parameters. In this paper, we have investigated the cell performance by exploring the photovoltaic properties of Mott Insulator LaVO3 (LVO). The LVO thin ?lms were grown by the sol–gel technique followed by a sintering pathway under various processing conditions. We investigated the in?uence of processing parameters on the structural, optical and electrical properties of the ?lms through different characterization techniques. A correlation between the material parameters with the device performance has been established to ensure LVO perovskite for photovoltaic applications. This analysis will aid researchers to realize Mott insulators as light absorber material.
关键词： photovoltaic material,Mott insulator,Thin ?lm solar cell,oxide perovskites
更新于2025-09-11 14:15:04
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Spectroscopic signature of trimer Mott insulator and charge disproportionation in
摘要： We have measured the re?ectivity spectra of the barium iridate 9R BaIrO3, the crystal structure of which consists of characteristic Ir3O12 trimers. In the high-temperature phase above the transition temperature Tc (cid:2) 180 K, we ?nd that the optical conductivity involves two temperature-dependent optical transitions with an ill-de?ned Drude response. These features are reminiscent of the optical spectra in the organic dimer Mott insulators, implying a possible emergence of an unusual electronic state named trimer Mott insulator in BaIrO3, where the carrier is localized on the trimer owing to the strong Coulomb repulsion. Along with a pronounced splitting of the phonon peak observed below Tc, which is a hallmark of charge disproportionation, we discuss a possible phase transition from the trimer Mott insulator to a charge-ordered insulating phase in BaIrO3.
关键词： phase transition,charge disproportionation,BaIrO3,optical conductivity,trimer Mott insulator
更新于2025-09-10 09:29:36
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Accurate Formula for the Macroscopic Polarization of Strongly Correlated Materials
摘要： The many-body Berry phase formula for macroscopic polarization is approximated by a sum of natural orbital geometric phases with fractional occupation numbers accounting for the dominant correlation effects. This formula accurately reproduces the exact polarization in the Rice?Mele?Hubbard model across the band insulator?Mott insulator transition. A similar formula based on a reduced Berry curvature accurately predicts the interaction-induced quenching of Thouless topological charge pumping.
关键词： natural orbital geometric phases,Rice?Mele?Hubbard model,Berry phase,macroscopic polarization,band insulator?Mott insulator transition,Thouless topological charge pumping
更新于2025-09-09 09:28:46
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Metal-insulator transition in V <sub/>2</sub> O <sub/>3</sub> thin film caused by tip-induced strain
摘要： We have demonstrated pressure-induced transition in a c-axis oriented vanadium sesquioxide (V2O3) thin film from a strongly correlated metal to a Mott insulator in a submicrometric region by inducing a local stress using contact atomic force microscopy. To have an access to a pressure range of sub-gigapascal, a tip with a large radius of 335 nm was prepared by chemical vapour deposition of platinum onto a commercial tip with a focused ion beam (FIB). The FIB-modified tip gives a good electrical contact at low working pressures (0.25–0.4 GPa) allowing unambiguously to evidence reversible metal-insulator transition in a pulsed laser-deposited V2O3 thin film by means of local investigations of current-voltage characteristics. A finite element method has confirmed that the diminution of the c/a ratio under this tip pressure explains the observed phase transition of the electron density of states in the film.
关键词： tip-induced strain,Mott insulator,metal-insulator transition,V2O3 thin film,atomic force microscopy
更新于2025-09-09 09:28:46
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Order parameter and detection for a finite ensemble of crystallized one-dimensional dipolar bosons in optical lattices
摘要： We explore the ground-state properties of a few bosons with dipole-dipole interactions in a one-dimensional optical lattice. For comparatively strong interactions, a transition from a Mott-insulator state to a crystal state occurs. Herein, we provide a detailed characterization and a detection protocol for the resulting crystal state. Using the eigenvalues of the reduced one-body density matrix, we define an order parameter that characterizes all the emergent states occurring in the finite-sized ensemble and agrees with the signatures obtained from the analysis of the one- and two-body densities. We further demonstrate that these few-body emergent states can be detected experimentally using the variance of single-shot measurements.
关键词： single-shot measurements,crystal state,dipolar bosons,optical lattice,Mott-insulator,order parameter
更新于2025-09-09 09:28:46
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Effective Three-Body Interactions in Jaynes-Cummings-Hubbard Systems
摘要： A generalisation of the Jaynes-Cummings-Hubbard model for coupled-cavity arrays is introduced, where the embedded two-level system in each cavity is replaced by a Ξ-type three-level system. We demonstrate that the resulting effective polariton-polariton interactions at each site are both two-body and three-body. By tuning the ratio of the two transition dipole matrix elements, we show that the strength and sign of the two-body interaction can be controlled whilst maintaining a three-body repulsion. We then proceed to demonstrate how different two-body and three-body interactions alter the mean field superfluid-Mott insulator phase diagram, with the possible emergence of a pair superfluid phase in the two-body attractive regime.
关键词： Jaynes-Cummings-Hubbard model,pair superfluid phase,three-level system,superfluid-Mott insulator phase transition,polariton-polariton interactions
更新于2025-09-09 09:28:46
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Floquet Engineering of Quantum Materials
摘要： Floquet engineering, the control of quantum systems using periodic driving, is an old concept in condensed matter physics dating back to ideas such as the inverse Faraday effect. However, there is a renewed interest in this concept owing to (a) the rapid developments in laser and ultrafast spectroscopy techniques, (b) discovery and understanding of various “quantum materials” hosting interesting exotic quantum properties, and (c) communication with different areas of physics such as artificial matter and nonequilibrium quantum statistical physics. Here, starting from a nontechnical introduction with emphasis on the Floquet picture and effective Hamiltonians, we review the recent applications of Floquet engineering in ultrafast, nonlinear phenomena in the solid state. In particular, Floquet topological states and their application to ultrafast spintronics and strongly correlated electron systems are overviewed.
关键词： ultrafast spintronics,Floquet topological systems,nonequilibrium quantum systems,Mott insulator
更新于2025-09-04 15:30:14