arXiv subjects

Jiadu Lin

Publications and source records attributed to Jiadu Lin.

4 recordsLinked to original sources

arXiv2026

Multipolar Light-Matter Hamiltonians in Symmetry-Breaking Photonic Vacuums

We show that the conventional multipolar Hamiltonian is qualitatively modified when the photonic vacuum breaks inversion or time-reversal symmetry. By explicitly applying the Power-Zienau-Woolley transformation, we derive the resulting multipolar Hamiltonians for two idealized chiral photonic environments: a spatial-chiral vacuum, which breaks inversion symmetry, and a temporal-chiral vacuum, which breaks time-reversal symmetry. In the spatial-chiral case, the transformation generates an inversion-breaking self-energy, whereas in the temporal-chiral case it produces an additional Zeeman-like energy. Using a trapped hydrogen-like atom and a charged harmonic oscillator in cavities as minimal examples, we show that these symmetry-dependent terms lead to characteristic spectral shifts. Our work provides a general framework for describing light-matter interactions in chiral quantum electrodynamics and identifying the associated symmetry-dependent effects on cavity-embedded atoms, molecules, and quantum materials.

quant-ph↗

arXiv2024

Engineering Ponderomotive Potential for Realizing $\pi$ and $\pi/2$ Bosonic Josephson Junctions

We study the ponderomotive potential of a bosonic Josephson junction periodically modulated by a high-frequency electromagnetic field. Within the small population difference approximation, the ponderomotive drive induces the well-known Kapitza pendulum effect, stabilizing a $\pi$-phase mode. We discuss the parameter dependence of the dynamical transition from macroscopic quantum self-trapping to $\pi$-Josephson oscillations. Furthermore, we examine the situation where the small population difference approximation fails. In this case, an essential momentum-shortening effect emerges, leading to a stabilized $\pi/2$-phase mode under certain conditions. By mapping this to a classical pendulum scenario, we highlight the uniqueness and limitations of the $\pi/2$-phase mode in bosonic Josephson junctions.

cond-mat.quant-gas↗

arXiv2024

Proposal for a Quantum Mechanical Test of Gravity at Millimeter Scale

The experimental verification of the Newton law of gravity at small scales has been a longstanding challenge. Recently, torsion balance experiments have successfully measured gravitational force at the millimeter scale. However, testing gravity force on quantum mechanical wave function at small scales remains difficult. In this paper, we propose a novel experiment that utilizes the Josephson effect to detect the different evolution of quantum phase induced from the potential difference caused by gravity. We demonstrate that this experiment can test gravity quantum mechanically at the millimeter scale, and also has a potential to investigate the parity invariance of gravity at small scales.

hep-ph↗

arXiv2023

Geometric phase driven Josephson junction: Possible experimental scheme for the search of spin superfluidity

We use the Gross-Pitaevskii equation to study Josephson tunneling between two weakly coupled Bose-Einstein condensates, which compose spin-1 bosons. We show that a rotating magnetic field on one side can produce a phase difference across the junction, resulting in an oscillatory tunneling spin current. Besides numerical calculation, we derive analytical results in two extreme cases, namely the low- and high-frequency limits: in the low-frequency limit (magnetic field rotates adiabatically), a non-Abelian geometric phase arises and leads to the oscillatory spin current. By sharp contrast, the physics is intrinsically different in the high-frequency limit, where an average Zeeman energy difference leads to an oscillatory spin current. This proposed apparatus should be promising for the future experimental search of spin superfluidity.

cond-mat.quant-gas↗