arXiv subjects

Shangguo Zhu

Publications and source records attributed to Shangguo Zhu.

8 recordsLinked to original sources

arXiv2026

Polarization-selective quantum cooperative response in dual-species atom arrays

Atom arrays have emerged as a powerful platform for quantum light-matter interfaces, yet single-species arrays are constrained by in-plane symmetry, restricting polarization control. Here we investigate the cooperative optical response of dual-species subwavelength atom arrays, in which intrinsic polarizability difference breaks in-plane symmetry. By engineering the lattice constants and detunings, the arrays exhibit polarization-dependent subradiant modes, enabling complete reflection of a specific polarization component. Leveraging this mechanism, we assemble array units as functional pixels and demonstrate a scalable polarization-selective quantum light modulator. Our work establishes a dynamically reconfigurable atomic-photonic platform for versatile subwavelength quantum optical elements.

quant-ph↗

arXiv2025

Tailoring Synthetic Gauge Fields in Ultracold Atoms via Spatially Engineered Vector Beams

Ultracold atoms, typically manipulated by scalar beams with uniform polarization, have propelled advances in quantum simulation, computation, and metrology. Yet, vector beams (VBs) -- structured light with spatially varying polarization -- remain unexplored in this context, despite their enhanced tunability and broad optical applications. Here, we demonstrate a novel scheme to generate synthetic gauge fields in ultracold atoms via VB-mediated coupling of internal states. This approach enables angular stripe phases across an expanded parameter range, achieving a three-order-of-magnitude enhancement in the phase diagram and facilitating experimental observation. We further present an all-optical method to create topologically nontrivial giant skyrmions in spin space, with tunable topology governed by VB parameters. Our findings establish VBs as powerful tools for quantum control and the exploration of exotic quantum states and phases.

cond-mat.quant-gas↗

arXiv2024

Parallel compression algorithm for fast preparation of defect-free atom arrays

Defect-free atom arrays have emerged as a powerful and versatile platform for quantum sciences and technologies, offering high programmability and promising scalability. The arrays can be prepared by rearranging atoms from a partially loaded initial array to the designated target sites. However, achieving large defect-free arrays presents challenges due to atom loss during rearrangement and the vacuum-limited lifetime which is inversely proportional to the array size. Efficient rearrangement algorithms which minimize time cost and atom loss are crucial for successful atom rearrangement. Here we propose a novel parallel compression algorithm which leverages multiple mobile tweezers to transfer atoms simultaneously. The total time cost could be reduced to scale linearly with the number of target sites. This algorithm can be readily implemented in current experimental setups.

quant-ph↗

arXiv2024

Tunnel-coupled optical microtraps for ultracold atoms

Arrays of individual atoms trapped in optical microtraps with micrometer-scale sizes have emerged as a fundamental, versatile, and powerful platform for quantum sciences and technologies. This platform enables the bottom-up engineering of quantum systems, offering the capability of low-entropy preparation of quantum states with flexible geometry, as well as manipulation and detection at the single-site level. The utilization of ultracold itinerant atoms with tunnel coupling in optical microtraps provides new opportunities for quantum simulation, enabling the exploration of exotic quantum states, phases, and dynamics, which would otherwise be challenging to achieve in conventional optical lattices due to high entropy and limited geometric flexibility. Here the development of tunnel-coupled optical microtraps for the manipulation of ultracold atomic quantum systems and its recent advances are briefly reviewed.

cond-mat.quant-gas↗

arXiv2022

Three-body recombination in a single-component Fermi gas with $p$-wave interaction

We study the three-body recombination of identical fermionic atoms. Using a zero-range model for the $p$-wave interaction, we show that the rate constant of three-body recombination into weakly bound $p$-wave dimers can be written as $α_{\rm rec} \propto v^{5/2}R^{1/2} k_T^4 (1+ C k_T^2 l_{\rm d}^2)$ for large and positive scattering volume $v$. Here $R$ is the $p$-wave effective range, $k_T^2$ gives the average thermal kinetic energy of the colliding atoms, and $l_{\rm d}$ is the size of the $p$-wave dimer. The leading term is different from the usually stated $v^{8/3}$-scaling law, but is consistent with an earlier two-channel calculation. For the subleading term, we compute the constant $C$ by solving the relevant three-body problem perturbatively when the parameter $γ\equiv R/v^{1/3}$ is small. The additional $C k_T^2 l_{\rm d}^2$ term provides important corrections for the temperature and interaction dependence of $α_{\rm rec}$, especially close to resonance when $k_T l_{\rm d}$ is relatively large.

cond-mat.quant-gas↗

arXiv2019

$d$-dimensional Lüscher's formula and the near-threshold three-body states in a finite volume

We study two particles colliding in a $d$-dimensional finite volume and generalize Lüscher's formula to arbitrary $d$ spatial dimensions. We obtain the $s$- and $p$-wave approximations of the generalized Lüscher's formula. For resonant $s$- or $p$-wave interactions, we analytically determine the energies of the low-lying states at large box size $L$. At $s$-wave resonance, we discover two low-lying states with nearly opposite energies, which are proportional to $\pm 1/L^{d/2}$ for $d\ge 5$, or $\pm 1/L^{2}\sqrt{\ln L}$ for $d=4$. This provides important insights into the near-threshold states of three bosons at a three-body resonance in a 2- or higher-dimensional finite volume.

nucl-th↗

arXiv2017

Three-body scattering hypervolumes of particles with short-range interactions

The low-energy scattering of three bosons or distinguishable particles with short-range interactions is characterized by a fundamental parameter, the three-body scattering hypervolume. Its imaginary part is directly related to the three-body recombination rate in a quantum gas consisting of such particles. We derive an analytical formula of it for weak interactions, and perform its first numerical calculations for bosons with a variable nonzero-range potential. For attractive interactions, we identify several three-body resonances at which the three-body scattering hypervolume becomes divergent or anomalously large.

cond-mat.quant-gas↗

arXiv2013

Universality in s-wave and higher partial wave Feshbach resonances: an illustration with a single atom near two scattering centers

It is well-known that cold atoms near s-wave Feshbach resonances have universal properties that are insensitive to the short-range details of the interaction. What is less known is that atoms near higher partial wave Feshbach resonances also have remarkable universal properties. We illustrate this with a single atom interacting resonantly with two fixed static centers. At a Feshbach resonance point with orbital angular momentum $L\ge1$, we find $2L+1$ shallow bound states whose energies behave like $1/R^{2L+1}$ when the distance $R$ between the two centers is large. We then compute corrections to the binding energies due to other parameters in the effective range expansions. For completeness we also compute the binding energies near s-wave Feshbach resonances, taking into account the corrections. Afterwards we turn to the bound states at large but finite scattering volumes. For p-wave and higher partial wave resonances, we derive a simple formula for the energies in terms of a parameter called "proximity parameter". These results are applicable to a free atom interacting resonantly with two atoms that are localized to two lattice sites of an optical lattice, and to one light atom interacting with two heavy ones in free space. Modifications of the low energy physics due to the long range Van der Waals potential are also discussed.

cond-mat.stat-mech↗