arXiv subjects

Matthew Edmonds

Publications and source records attributed to Matthew Edmonds.

15 recordsLinked to original sources

arXiv2026

Emergence of giant vortices under nonlinear rotation with attractive interactions in a toroidal condensate

We numerically investigate the effects of a density-dependent gauge potential which induces nonlinear rotation on a Bose-Einstein condensate confined in a toroidal trapping geometry. By focusing on the resulting vortex lattice configurations, we demonstrate that increasing the strength of the nonlinear rotation leads to a structural transition from a ring-shaped vortex lattice to a giant vortex state. The quantum circulation associated with the giant vortex is found to be highly sensitive to the strength of the nonlinear rotation and the giant vortex appears in the regime of negative chemical potential. Additionally, we identify the parameter regime in which the Thomas-Fermi density profile remains valid by mapping the solution space based on the strength of the nonlinear rotation and the radius of the confining potential. Based on the Bogoliubov de Gennes analysis, we investigate the impact of nonlinear rotation on the collective excitation spectrum. Our results reveal a violation of the Kohn theorem, accompanied by changes in the breathing mode frequency that indicate radial deformation of the condensate. Our findings are further substantiated through a comprehensive hydrodynamic analysis. Finally, we analyze the stability of multiply quantized vortices under nonlinear rotation. Our findings indicate that while nonlinear rotation can enhance the global stability of these states, it does not necessarily ensure their local stability.

cond-mat.quant-gas↗

arXiv2025

Photoacoustic model for laser-induced acoustic desorption of nanoparticles

Laser-induced acoustic desorption (LIAD) enables loading nanoparticles into optical traps under vacuum for levitated optomechanics experiments. Current LIAD systems rely on empirical optimization using available laboratory lasers rather than systematic theoretical design, resulting in large systems incompatible with portable or space-based applications. We develop a theoretical framework using the photoacoustic wave equation to model acoustic wave generation and propagation in metal substrates, enabling systematic optimization of laser parameters. The model identifies key scaling relationships: surface acceleration scales as $\tau^{-2}$ with pulse duration, while acoustic diffraction sets fundamental limits on optimal spot size $w \gtrsim \sqrt{v\tau d}$. Material figures of merit combine thermal expansion and optical absorption properties, suggesting alternatives to traditional aluminum substrates. The framework validates well against experimental data and demonstrates that compact laser systems with sub-nanosecond pulse durations can achieve performance competitive with existing laboratory-scale implementations despite orders-of-magnitude lower pulse energies. This enables rational design of minimal LIAD systems for practical applications.

physics.optics↗

arXiv2025

Polar core vortex dynamics in disc-trapped homogeneous spin-1 Bose-Einstein condensates

We study the dynamics of polar core vortices in the easy plane phase of an atomic spin-1 Bose-Einstein condensate confined in a two-dimensional disc potential. A single vortex moves radially outward due to its interaction with background flows that arise from boundary effects. Pairs of opposite sign vortices, which tend to attract, move either radially inward or outward, depending on their strength of attraction relative to boundary effects. Pairs of same sign vortices repel. Spiral vortex dynamics are obtained for same-sign pairs in the presence of a finite axial magnetization. We quantify the dynamics for a range of realistic experimental parameters, finding that the vortex dynamics are accelerated with increasing quadratic Zeeman energy, consistent with existing studies in planar systems.

cond-mat.quant-gas↗

arXiv2025

Excitation spectrum of vortex-lattice modes in a rotating condensate with a density-dependent gauge potential

We investigate the collective excitation spectrum of a quasi-2D Bose-Einstein condensate trapped in a harmonic confinement with nonlinear rotation induced by a density-dependent gauge field. Using a Bogoliubov-de Gennes(BdG) analysis, we show that the dipole mode frequency depends strongly on the nonlinear interaction strength, violating Kohn's theorem. Further utilizing the variational analysis, we derive analytical expressions for the dipole and breathing modes, which suggests a strong dependence of the condensate's width on the nonlinear rotation resulting from the density-dependent gauge potential. We identify four different vortex displacement modes -- namely Tkachenko, circular, quadratic, and rational-whose frequencies are sensitive to the nonlinear rotation. In addition to the numerical analysis, we also derive an analytical expression for the Tkachenko mode frequency using a Hydrodynamic approach that agrees well with the frequencies obtained by the Fourier analysis of the transverse and longitudinal vortex dynamics induced by a Gaussian perturbation as well as the frequencies from the BdG excitation spectrum. Our findings also reveal that the excitation spectrum remain symmetric around the angular quantum number $l=0$, with modified energy splitting between $l$ and $-l$ as the nonlinear rotation changes from negative to positive values. Finally, we demonstrate that the surface mode excitation frequency increases (decreases) with an increase in the positive (negative) nonlinear rotation strength.

cond-mat.quant-gas↗

arXiv2025

Quantum droplets in a beyond-mean-field density-dependent gauge theory

The beyond-mean-field corrections appropriate to a bosonic many-body system experiencing a density-dependent gauge potential are derived, and from this the dimensional hierarchy of quantum droplet solutions are explored. Non-stationary quantum droplet solutions are supported by a single interaction parameter characterising the strength of the gauge potential, while in one dimension the beyond-mean-field theory can be solved exactly to yield chiral quantum droplets and dark soliton-like excitations. Numerical simulations of single and pairs of chiral droplets indicate a rich dynamics in the beyond-mean-field regime.

cond-mat.quant-gas↗

arXiv2023

Quantum vacuum effects in non-relativistic quantum field theory

Nonlinearities in the dispersion relations associated with different interactions designs, boundary conditions and the existence of a physical cut-off scale can alter the quantum vacuum energy of a nonrelativistic system nontrivially. As a material realization of this, we consider a 1D-periodic rotating, interacting non-relativistic setup. The quantum vacuum energy of such a system is expected to comprise two contributions: a fluctuation-induced quantum contribution and a repulsive centrifugal-like term. We analyze the problem in detail within a complex Schoedinger quantum field theory with a quartic interaction potential and perform the calculations non-perturbatively in the interaction strength by exploiting the nonlinear structure of the associated nonlinear Schroedinger equation. Calculations are done in both zeta-regularization, as well as by introducing a cut-off scale. We find a generic, regularization-independent behavior, where the competition between the interaction and rotation can be balanced at some critical ring-size, where the quantum vacuum energy has a maxima and the force changes sign. The inclusion of a cut-off smoothes out the vacuum energy at small distance but leaves unaltered the long distance behavior. We discuss how this behavior can be tested with ultracold-atoms.

hep-th↗

arXiv2022

Quantum vacuum, rotation, and nonlinear fields

In this paper, we extend previous results on the quantum vacuum or Casimir energy, for a noninteracting rotating system and for an interacting nonrotating system, to the case where both rotation and interactions are present. Concretely, we first reconsider the noninteracting rotating case of a scalar field theory and propose an alternative and simpler method to compute the Casimir energy based on a replica trick and the Coleman-Weinberg effective potential. We then consider the simultaneous effect of rotation and interactions, including an explicit breaking of rotational symmetry. To study this problem, we develop a numerical implementation of zeta function regularization. Our work recovers previous results as limiting cases and shows that the simultaneous inclusion of rotation and interactions produces nontrivial changes in the quantum vacuum energy. Besides expected changes (where, as the size of the ring increases for fixed interaction strength, the angular momentum grows with the angular velocity), we notice that the way rotation combines with the coupling constant amplifies the intensity of the interaction strength. Interestingly, we also observe a departure from the typical massless behavior where the Casimir energy is proportional to the inverse size of the ring.

hep-th↗

arXiv2022

Dark quantum droplets and solitary waves in beyond-mean-field Bose-Einstein condensate mixtures

Quantum liquid-like states of matter have been realized in an ongoing series of experiments with ultracold Bose gases. Using a combination of analytical and numerical methods we identify the specific criteria for the existence of dark solitons in beyond-mean-field binary condensates, revealing how these excitations exist for both repulsive and attractive interactions, the latter leading to dark quantum droplets with properties intermediate between a dark soliton and a quantum droplet. The phenomenology of the these excitations are explored within the full parameter space of the model, revealing the novel spatial profile of the excitation that differs significantly from the Zakharov-Shabat (ZS) soliton; leading to a negative effective mass that is enhanced in the presence of the quantum fluctuations. Finally the dynamics of pairs of the excitations are explored, showing non-integrable dynamics and dark soliton bound-states in the attractive regime.

cond-mat.quant-gas↗

arXiv2021

Few-to-many vortex states of density-angular-momentum coupled Bose-Einstein condensates

Motivated by recent experiments, we theoretically study a gas of atomic bosons confined in an elliptical harmonic trap; forming a quasi-two-dimensional atomic Bose-Einstein condensate subject to a density-dependent gauge potential which realises an effective density-angular-momentum coupling. We present exact Thomas-Fermi solutions which allows us to identify the stable regimes of the full parameter space of the model. Accompanying numerical simulations reveal the effect of the interplay of the rigid body and density-angular-momentum coupling for the elliptically confined condensate. By varying the strength of the gauge potential and trap anisotropy we explore how the superfluid state emerges in different experimentally accessible geometries, while for large rotation strengths dense vortex lattices and concentric vortex ring arrangements are obtained.

cond-mat.quant-gas↗

arXiv2020

Synthetic superfluid chemistry with vortex-trapped quantum impurities

We explore the effect of using two-dimensional matter-wave vortices to confine an ensemble of bosonic quantum impurities. This is modelled theoretically using a mass-imbalanced homogeneous two component Gross-Pitaevskii equation where each component has independent atom numbers and equal atomic masses. By changing the mass imbalance of our system we find the shape of the vortices are deformed even at modest imbalances, leading to barrel shaped vortices; which we quantify using a multi-component variational approach. The energy of impurity carrying vortex pairs are computed, revealing a mass-dependent energy splitting. We then compute the excited states of the impurity, which we in turn use to construct `covalent bonds' for vortex pairs. Our work opens a new route to simulating synthetic chemical reactions with superfluid systems.

cond-mat.quant-gas↗

arXiv2020

Vortex patterns of atomic Bose-Einstein condensates in a density-dependent gauge potential

We theoretically examine the vortex states of a gas of trapped quasi-two-dimensional ultracold bosons subject to a density-dependent gauge potential, realizing an effective nonlinear rotation of the atomic condensate, which we also show is within the reach of current experimental techniques with ultracold atom experiments. The nonlinear rotation has a two-fold effect; as well as distorting the shape of the condensate it also leads to an inhomogeneous vorticity resulting in novel morphological and topological states, including ring vortex arrangements that do not follow the standard Abrikosov result. The dynamics of trapped vortices are also explored, which differs from the case of rigid-body rotation due to the absence of a global laboratory reference frame.

cond-mat.quant-gas↗

arXiv2020

Quantum droplets of quasi-one-dimensional dipolar Bose-Einstein condensates

Ultracold dipolar droplets have been realized in a series of ground-breaking experiments, where the stability of the droplet state is attributed to beyond-mean-field effects in the form of the celebrated Lee-Huang-Yang (LHY) correction. We scrutinize the dipolar droplet states in a one-dimensional context using a combination of analytical and numerical approaches, and identify experimentally viable parameters for accessing our findings for future experiments. In particular we identify regimes of stability in the restricted geometry, finding multiple roton instabilities as well as regions supporting quasi-one-dimensional droplet states. By applying an interaction quench to the droplet, a modulational instability is induced and multiple droplets are produced, along with bright solitons and atomic radiation. We also assess the droplets robustness to collisions, revealing population transfer and droplet fission.

cond-mat.quant-gas↗

arXiv2014

Elementary excitations of chiral Bose-Einstein condensates

We study the collective modes of a Bose-Einstein condensate subject to an optically induced density-dependent gauge potential. The corresponding interacting gauge theory lacks Galilean invariance, yielding an exotic superfluid state. The nonlinear dynamics in the presence of a current nonlinearity and an external harmonic trap are found to give rise to dynamics which violate Kohn's theorem; where the frequency of the dipole mode strongly depends on the strength of the mass current in the gas. The linearised spectrum reveals how the centre of mass and shape oscillations are coupled, whereas in the strongly nonlinear regime the dynamics is irregular.

cond-mat.quant-gas↗

arXiv2013

On the Josephson effect in a Bose-Einstein condensate subject to a density dependent gauge potential

We investigate the coherent dynamics of a Bose-Einstein condensate in a double well, subject to a density dependent gauge potential. Further, we derive the nonlinear Josephson equations that allow us to understand the many-body system in terms of a classical Hamiltonian that describes the motion of a nonrigid pendulum with an initial angular offset. Finally we analyze the phase-space trajectories of the system, and describe how the self-trapping is affected by the presence of an interacting gauge potential.

cond-mat.quant-gas↗

arXiv2012

Simulating an interacting gauge theory with ultracold Bose gases

We show how density dependent gauge potentials can be induced in dilute gases of ultracold atoms using light-matter interactions. We study the effect of the resulting interacting gauge theory and show how it gives rise to novel topological states in the ultracold gas. We find in particular that the onset of persistent currents in a ring geometry is governed by a critical number of particles. The density-dependent gauge potential is also found to support chiral solitons in a quasi-one-dimensional ultracold Bose gas.

cond-mat.quant-gas↗