arXiv subjects

Jinxiong Jia

Publications and source records attributed to Jinxiong Jia.

9 recordsLinked to original sources

arXiv2026

Observation of interaction-induced fast Thouless pumping of solitons

Thouless pumping provides a paradigmatic platform for studying the effects of interactions on topological transport in periodically driven systems. However, most studies have been constrained by adiabatic conditions, which preclude exploration of interaction-driven novel topological states at high driving frequencies. Here, we experimentally investigate the interplay between interaction and modulation frequency in Thouless pumping realized in a periodically modulated lattice in momentum space of atomic Bose-Einstein condensate. We observe fast Thouless pumping of matterwave solitons at intermediate interactions, with no counterpart in the non- or weakly interacting regimes. Beyond the boundary of topological phase transition induced by interaction, nonadiabatic quantized pumping of solitons emerges at high modulation frequencies over a broad interaction range, in good agreement with theoretical calculations, while the solitons remain trapped in the low-frequency adiabatic pumping regime. Our work opens new avenues for accelerating topological transport in driven quantum systems and engineering fast topological devices.

cond-mat.quant-gas↗

arXiv2026

Geometry-Driven Nonlinear Orbital Magnetoelectric Effect

We propose a nonlinear orbital magnetoelectric effect, which generates orbital magnetization quadratically in centrosymmetric materials where the linear orbital magnetoelectric effect is strictly forbidden. Using extended semiclassical formulation, we derive a gauge-invariant microscopic theory that separates intrinsic and extrinsic contributions and establishes their distinct dependence on the relaxation time, providing an experimental discriminator. In two-dimensional systems the nonlinear response is far less constrained by out-of-plane rotational symmetries than the linear orbital magnetoelectric effect, substantially enlarging the materials platform. Microscopically, the dominant contributions are governed by a Hermitian-connection structure. Finally, we estimate that the magnitude of the nonlinear orbital magnetoelectric effect lies within the sensitivity of state-of-the-art magneto-optical Kerr measurements.

cond-mat.mes-hall↗

arXiv2026

Quantum geometric map of magnetotransport

We propose a quantum geometric map for the magnetononlinear Hall effect (MNHE), the planar Hall effect (PHE), and the ordinary Hall effect (OHE). These magnetotransport phenomena originate from the bilinear charge current of Bloch electrons in electromagnetic fields, incorporating both spin Zeeman coupling and orbital minimal coupling to the applied magnetic field. Benchmarked against Onsager reciprocity, we demonstrate that the spin- and orbital-induced MNHEs are governed by the time-reversal-even Zeeman quantum metric dipole and conventional quantum metric quadrupole, respectively; the spin- and orbital-induced PHEs are dominated by the time-reversal-odd Zeeman Berry curvature dipole and conventional Berry curvature quadrupole, respectively. We further show that the OHE contains an interband contribution that is related to the quantum metric quadrupole, contrary to conventional wisdom. Navigated by this map, we study the previously unexplored spin-induced PHE in the surface Dirac cone of topological insulators, where we uncover a step-like PHE. Our work offers a unified quantum geometric framework for understanding magnetotransport experiments.

cond-mat.mes-hall↗

arXiv2026

Quantum Geometric Entropy Production and Entropy Hall Effect

Quantum geometry, encoded in the Berry curvature and quantum metric, has unified diverse anomalous transport phenomena in solids, yet a microscopic quantum-geometric theory of entropy transport for Bloch electrons is still lacking. We formulate an entropy continuity equation for noninteracting fermions driven by an electric field, starting from the von Neumann entropy, and obtain quantum-mechanical expressions for the entropy current density and entropy production rate. Introducing relaxation through a relaxation-time dissipator, we identify the quantum metric as the origin of the leading entropy production, providing a direct microscopic diagnostic of dissipation in both the extrinsic Drude response and an intrinsic nonlinear Ohmic contribution controlled by quantum metric. We further predict an entropy Hall effect arising from the Berry curvature and show that it obeys an Onsager reciprocal relation with the anomalous Nernst effect under a temperature gradient. Finally, we establish universal relations connecting entropy and charge currents under DC and AC driving, offering experimentally accessible probes of quantum geometry through nonequilibrium entropy flow.

cond-mat.stat-mech↗

arXiv2025

Nonlinear Magnetoelectric Edelstein Effect

The linear Edelstein effect is a cornerstone phenomenon in spintronics that describes the generation of spin magnetization in response to an applied electric field. Recent theoretical advances have reignited interest in its nonlinear counterpart, the nonlinear Edelstein effect, in which spin magnetization is induced by a second-order electric field. However, the intrinsic contribution to both effects is generally forbidden in systems preserving time-reversal symmetry ($\mathcal{T}$) or composite symmetries such as $\mathcal{T}τ_{1/2}$, where $τ_{1/2}$ denotes a half-lattice translation. In such systems, spin magnetization typically emerges either from extrinsic mechanisms but limited to metals due to their Fermi-surface property, or from dynamical electric fields with a terahertz driving frequency. Here, we propose a new mechanism for spin magnetization, arising from the interplay of magnetic and electric fields, termed the nonlinear magnetoelectric Edelstein effect. Remarkably, its intrinsic component, determined purely by the material's band structure, can appear even in $\mathcal{T}$-invariant materials, but lacking inversion symmetry ($\mathcal{P}$), including insulators. On the other hand, we illustrate that its extrinsic component can serve as a sensitive indicator of the Néel vector reversal in $\mathcal{P}\mathcal{T}$-symmetric antiferromagnetic materials, offering a novel route for antiferromagnetic order detection. To validate our theory, we perform explicit calculations using a two-band Dirac model and a tight-binding model on a honeycomb lattice, finding that both effects yield sizable spin magnetization. Our findings establish the nonlinear magnetoelectric Edelstein effect as a versatile platform for both exploring nonlinear spin physics and enabling symmetry-based detection of antiferromagnetic order.

cond-mat.mes-hall↗

arXiv2025

Intrinsic gyrotropic magnetic current from Zeeman quantum geometry

Quantum geometric tensor (QGT), which is usually obtained by evaluating the quantum distance between Bloch states parametrized by momentum, plays a key role in exploring the exotic responses of quantum materials. Herein, we revisit the concept of QGT by further taking into account the spin degree of freedom. Besides the conventional QGT relating to momentum translation, we uncover a new QGT (termed Zeeman QGT) relating to momentum translation as well as spin rotation, whose imaginary (real) part gives the Zeeman Berry curvature (quantum metric). Notably, we show that these novel quantum geometric quantities can drive an intrinsic gyrotropic magnetic current (IGMC) in spin-orbit coupled materials when the electron spin is steered by an oscillating magnetic field. With symmetry analysis, we show that a wide range of materials can support the IGMC, as illustrated by model calculations. Finally, we discuss the experimental aspects of detecting the IGMC driven by Zeeman QGT.

cond-mat.mes-hall↗

arXiv2024

Equivalence of semiclassical and response theories for second-order nonlinear ac Hall effects

It has been known that the semiclassical theory and the response theory can equivalently give the Drude and the intrinsic anomalous Hall conductivities in the linear order of electric field. However, recent theoretical advances implied that the second-order nonlinear conductivities calculated with both approaches are no longer equivalent, which leads to various experimental explanations even in a similar experimental setup conducted in \href{https://www.science.org/doi/10.1126/science.adf1506}{[\textit{Science \textbf{381}, 181 (2023)}]} and \href{https://www.nature.com/articles/s41586-023-06363-3}{[\textit{Nature \textbf{621}, 487 (2023)}]}, respectively. Herein, by extending the AC semiclassical theory up to the second order of electric field, we show that the semiclassical theory is still equivalent to the response theory in the second order of electric field when the relaxation is taken into account on the same footing. In particular, we show that the familiar second-order nonlinear current responses, including the nonlinear Drude current and the Berry curvature (quantum metric) dipole driven extrinsic (intrinsic) nonlinear Hall current, can be derived by both approaches. Further, we show that the quantum-corrected intrinsic nonlinear longitudinal current, as recently proposed by the response theory or in a similar manner, can also be reproduced by the semiclassical theory. Beyond those known second-order current responses, with both approaches, we uncover two previously overlooked nonlinear displacement currents unique to the AC electric field. As a consequence of this equivalence,...

cond-mat.mes-hall↗

arXiv2024

Fusion Rules of Majorana-Kramer-Pairs in Time-Reversal-Invariant Topological Superconductors

We theoretically investigate the fusion rules of Majorana Kramers pairs in time-reversal-invariant topological superconductors. We find that the fusion of Majorana Kramers pairs is a process that Ising anyons fuse independently in the two distinct time-reversal sectors. Considering the full fusion including the initialization and the fusion, we explore the observation of a supersymmetry that emerges in time-reversal-invariant topological superconductors, and design the schemes for the nontrivial fusion and the trivial fusion to show the non-Abelian statistics of Majorana Kramers pairs. We also show the possible influence of local adiabatic mixing on the fusion and the differentiation between distinct fusion processes remains feasible even in the presence of such mixing. Our proposals are applied in $d_{x^2-y^2}$-wave topological superconductors, and the theoretical framework can be extended to the fusion of multiple Majorana zero modes protected by unitary symmetry.

cond-mat.supr-con↗

arXiv2024

Braiding Induced by Finite-Size Effect in One-Dimensional Topological Superconductors

We investigate the transport properties of Majorana zero mode (MZM) and Majorana Kramers pair (MKP) in one-dimensional topological superconductors, respectively. An effective model is established for braiding of MZMs and MKPs. We employ the $d_{x^{2}-y^{2}}$-wave topological superconductors to embody the effective model for braiding of MKPs by utilizing finite-size effects and locally tunable coupling parameters. We show how to construct the state initialization and readout via gate control. We also use this method for braiding MZMs in s-wave topological superconductors. Our proposal presents a promising avenue for experimentally verifying the non-Abelian statistical properties of MZMs and MKPs, with implications for topological quantum computing.

cond-mat.mes-hall↗