arXiv subjects

Zhenzhong Xing

Publications and source records attributed to Zhenzhong Xing.

3 recordsLinked to original sources

arXiv2026

Rapid multi-mode trapped-ion laser cooling in a phase-stable standing wave

Laser cooling is fundamental to quantum computing and metrology using atomic systems. Precise control often requires cooling atoms' motional degrees of freedom to the quantum ground state, imposing operation time and architectural limitations particularly in large-scale systems. Here we demonstrate how the integrated optical control of interest for scaling trapped-ion systems additionally enables laser cooling that bypasses limitations of conventional schemes. Leveraging multi-channel integrated delivery of ultraviolet to infrared wavelengths for calcium ion control including in passively phase-stable ultraviolet standing waves (SWs), we experimentally verify a long-standing prediction by Cirac et al., realizing Doppler cooling to below the conventional Doppler limit at a SW node. We also present the first realization of ground-state cooling via electromagnetically induced transparency (EIT) using a ``probe" beam delivered as a SW with atoms positioned at a node, predicted to enable multi-mode sub-recoil-limit laser cooling. We demonstrate cooling of motional modes spanning an approximately 5 MHz bandwidth from the Doppler temperature to near the ground state within 150~\textmu s, reaching $\bar n \approx 0.05$ phonon number occupancies for the target mode. Direct evaluation against the comparable running-wave (RW) scheme shows the SW implementation's simultaneous advantage in cooling rate, motional mode bandwidth, and final phonon number, as previously theoretically predicted. Our work leverages capabilities enabled by integrated optical delivery to demonstrate fast cooling of multiple modes to the quantum ground state, and more broadly how scalable approaches to optical control can enable enhancements in fundamental atomic functionalities.

physics.atom-ph↗

arXiv2025

Trapped-ion laser cooling in structured light fields

Laser cooling is fundamental to quantum computation and metrology with trapped ions, and can occupy a majority of runtime in current systems. A key limitation to cooling arises from unwanted carrier excitation, which in typically used running wave (RW) fields invariably accompanies the sideband transitions effecting cooling. We consider laser cooling in structured light profiles enabling selective sideband excitation with nulled carrier drive; motivated by integrated photonic approaches' passive phase and amplitude stability, we propose simple configurations realizable with waveguide addressing using either standing wave (SW) or first-order Hermite-Gauss (HG) modes. We quantify performance of Doppler cooling from beyond the Lamb-Dicke regime (LDR), and ground-state (GS) cooling using electromagnetically induced transparency (EIT) leveraging these field profiles. Carrier-free EIT offers significant benefits simultaneously in cooling rate, motional frequency bandwidth, and final phonon number. Carrier-free Doppler cooling's advantage is significantly compromised beyond the LDR but continues to hold, indicating such configurations are applicable for highly excited ions. Our simulations focus on level structure relevant to $^{40}$Ca$^+$, though the carrier-free configurations can be generally applied to other species. We also quantify performance limitations due to polarization and modal impurities relevant to experimental implementation. Our results indicate potential for simple structured light profiles to alleviate bottlenecks in laser cooling, and for scalable photonic devices to improve basic operation quality in trapped-ion systems.

physics.atom-ph↗

arXiv2025

Geometrodynamics of a 2D Curved Surface due to a Constrained Quantum Particle via its Gravitational Dual: $\mathbf{\mathcal{S}^2}$ Analytical Model Calculations

We provide a unique and novel extension of da Costa's calculation of a quantum mechanically constrained particle. This is achieved by analyzing the perturbative back reaction of the quantum confined particle's eigenstates and spectra upon the geometry of the curved surface itself, thereby addressing the problem of shape optimization in this model. We do this by first formulating a two-dimensional action principle of the quantum constrained particle, which upon variation of the wave function reproduces Schrödinger's equation including da Costa's surface curvature-induced potentials. We further demonstrate that our derived action principle is dual to a two-dimensional dilation gravity theory and we vary its functional with respect to the embedded two-dimensional inverse-metric to obtain the respective geometrodynamical Einstein equation. We solve this resulting Einstein equation perturbatively by first solving the da Costa's Schrödinger equation to obtain an initial eigensystem, which is used as initial-input data for a perturbed metric inserted into the derived Einstein equation. As a proof of concept, we perform this calculation on a two-sphere and show its first iterative perturbed shape evolution. We also turn on external electromagnetic fields and formulate the full field theoretic field equations for future investigation. The external fields manifest themselves via a surface induced, pulled-back $U(1)$ coupling in our two-dimensional dual gravity theory, thereby revealing interesting and rich new surface physics in this specific paradigm.

hep-th↗