Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1912.07073

Twisted superfluids in moving frame

A. Yu. Okulov

Published Dec 15, 2019• 0 citations
arXivHTMLPDF

Abstract

Helical waveguide filled by superfluid is shown to transform rotations of the reference frame $\vec Ω_{\oplus}$ into linear displacements of the atomic ensemble and vise versa the linear displacements of the reference frame $\vec V$ initialize rotations $\vec Ω_{\oplus}$ of ensemble. In the mean-field Gross-Pitaevskii equation with a weakly modulated gravitation potential the exact solutions for macroscopic wavefunction $Ψ$ demonstrate the emergence of $redshift$ phase factor. For helical waveguides formed by phase-conjugated optical vortices with high angular momentum $L_z=\pm \ell \hbar \sim \pm \hbar \cdot 10^{3 ÷4}$ one may expect the significant improvement of the phase-sensitivity $δϕ$ by factor containing $2 \ell$ compared to the conventional nonsingular matter-wave interferometry.

DOI
10.48550/arxiv.1912.07073

Related papers

An Optical Analog for a Rotating Binary Bose—Einstein Condensate

V. P. Ruban

Coupled nonlinear Schrödinger equations for paraxial optics with two circular polarizations of light in a defocusing Kerr medium with anomalous dispersion coincide in form with the Gross–Pitaevskii equations for a binary Bose—Einstein condensate (BEC) of cold atoms in the phase separation regime. In this case, the helical symmetry of an optical waveguide corresponds to rotation of the transverse potential confining the BEC. The “centrifugal force” considerably affects the propagation of a light wave in such a system. Numerical experiments for a waveguide with an elliptical cross section have revealed characteristic structures consisting of quantized vortices and domain walls between two polarizations, which have not been observed earlier in optics.

Журнал Экспериментальной и Теоретической Физики•Dec 15, 2023•2 citations

The physics of rotational atomic and photonic quantum fluids

Albert Gallemí Camacho

In this thesis, we will study the superfluidity of condensed atomic and photonic systems, through the manipulation of rotational states, such as vortices or persistent currents. We will study Bose-Einstein condensates both in the strongly-correlated regime, where models based on second quantization, like Bose-Hubbard model, will be required; and in weakly-interacting systems, where mean-field approximations will be accurate enough, and the system is described by means of the Gross-Pitaevskii equation.\n\n\t\t\t\t We will start with the analysis of the fundamental properties of Bose gases trapped in few-site lattices, such as the phase diagram, the condensed fractions and the entanglement. Concerning the phases, we will study the properties of the transitions between them and, in particular, their characteristic critical exponents.\n\n\t\t\t\t Afterwards, we will consider the sites of a lattice constituting a ring geometry and study the effect of manipulating the tunnelling rate between two of the wells. This kind of tunable link is called weak link, and we will analyze what happens in the mean-field approximation, in comparison with the strongly-correlated case. In both regimes we will observe that the weak link behaves as a key element in the system in order to generate superpositions of flow states. Moreover, in the mean-field case, we can identify an energy barrier that separates two current states (also known as winding number states), where solitonic states, i.e. states characterized by the presence of topological singularities, live. Such a barrier will be the origin of the appearance of a hysteresis cicle in processes of transfer between different winding number curves, called phase slips.\n\n\t\t\t\t After that, we will study two coherently-coupled components of a toroidally-trapped Bose-Einstein condensate. We will see that when we imprint a persistent current in one of the components, there is an angular momentum transfer between both components. This transfer can be identified as a phase slip event, and the tunability of the system allows it to behave as a robust qubit, due to the fact that states supported by currents are less fragile.\n\n\t\t\t\t In two-component condensates, it is possible to find a particular solitonic state called Josephson vortex. This state is characterized by a density depletion around a point with nonzero currents. Moreover, these states are energetically more favourable than dark soliton states, whose main difference with respect to Josephson vortices is the fact that dark solitons do not present currents. However, when spin-orbit coupling is added, dark soliton states are no longer possible, but Josephson vortices persist. In this thesis, we will see that these states decay through transversal excitations (i.e. snake instability), producing vortex-antivortex pairs, and their subsequent dynamical evolution depends on the initial orientation of the Josephson vortex.\n\n\t\t\t\t Finally, we will move to the field of polariton condensates. Polaritons are quasiparticles product of the coupling between photons and excitons (which are electron-hole excitations) in semiconductor microcavities. These particles can constitute an out-of-equilibrium (due to the short lifetime of polaritons) Bose-Einstein condensate described by the Gross-Pitaevskii-like equation for two components, because of the two polarization components inherent to the photonic nature of polaritons. The cavities where these condensates are created generate a spin-orbit coupling between the two polariton components, in such a way that current states with different orbital angular momentum are coupled. This yields to a phenomenon of spin-to-orbital angular momentum conversion that we will study in ring-trapped polariton condensates. At the end of this thesis, we will probe the superfluid properties of polariton condensates, by analyzing the response of the generated currents against the presence of disorder.

•Sep 13, 2017•0 citations

Macroscopic wavefunction for ensemble of ultracold atoms trapped in optical labyrinth

A. Yu. Okulov

We discuss a possibility of a pinning of quantized matter wave vortices by optical vortices in specially arranged optical dipole traps. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum to support "antiferromagnet-like" matter waves. The separable Hamiltonian for matter waves is proposed which allows to factorize of the 3D - wavefunction exactly in a product of 1D - harmonic oscillator's ground state and 2D - vortex-antivortex wavefunction. The wavefunction's phase gradient field associated with the field of classical velocities via Madelung transformation forms labyrinth-like structure. The macroscopic wavefunction of periodically spaced BEC superfluid vortices appears to be less influenced by decoherence.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 3, 2008•0 citations

Renormalization-group calculation of superfluid density and helicity modulus

Miguel Calvo

The field-theoretical renormalization-group techniques previously developed for the description of the mestastable phases of isotropic, homogeneous, $d$-dimensional systems, which (close to their critical temperature) can be described in terms of the Landau-Ginzburg-Wilson functional integral with a two-component order parameter, and applied to obtain the scaling form of the helicity modulus, defined as a measure of the free-energy increment associated with a metastable, helical twisting of the order parameter. The general scaling form of this quantity is determined even in the presence of an external helical field, for arbitrary helix pitch and temperature. In the case of vanishing external field, this quantity represents the superfluid density and is a function of the temperature and the superfluid velocity (which corresponds to the inverse of the helix pitch). In the limit of small velocities this expression exhibits the well-known Josephson asymptotic form ${\ensuremath{\rho}}_{s}\ensuremath{\sim}{({T}_{c}\ensuremath{-}T)}^{\ensuremath{\nu}(d\ensuremath{-}2)}={({T}_{c}\ensuremath{-}T)}^{2\ensuremath{\beta}\ensuremath{-}\ensuremath{\nu}\ensuremath{\eta}}$. An explicit $\ensuremath{\epsilon}=4\ensuremath{-}d$ expansion for the helicity modulus is presented in the case of arbitrary external field to the one-loop approximation.

Physical review. B, Condensed matter•Dec 1, 1981•1 citation

Vortex-antivortex wavefunction of a degenerate quantum gas

A. Yu. Okulov

A mechanism of a pinning of the quantized matter wave vortices by optical vortices in a specially arranged optical dipole traps is discussed. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum and form the “antiferromagnet”-like matter waves. The separable Hamiltonian for matter waves in pancake trapping geometry is proposed and 3D-wavefunction is factorized in a product of wavefunctions of the 1D harmonic oscillator and 2D vortex-antivortex quantum state. The 2D wavefunction’s phase gradient field associated via Madelung transform with the field of classical velocities forms labyrinth-like structure. The macroscopic quantum state composed of periodically spaced counter-rotating BEC superfluid vortices has zero angular momentum and nonzero rotational energy.

arXiv:0908.0237•Laser Physics•Aug 1, 2009•10 citations

Dynamics of Quantized Vortices in Superfluid Helium and Rotating Bose-Einstein Condensates

Makoto Tsubota, Kenichi Kasamatsu

arXiv:cond-mat/0309364•Journal of Low Temperature Physics•Feb 1, 2005•8 citations
Helical waveguide filled by superfluid is shown to transform rotations of the reference frame Ω⃗⊕\vec Ω_{\oplus}Ω⊕​ into linear displacements of the atomic ensemble and vise versa the linear displacements of the reference frame V⃗\vec VV initialize rotations Ω⃗⊕\vec Ω_{\oplus}Ω⊕​ of ensemble. In the mean-field Gross-Pitaevskii equation with a weakly modulated gravitation potential the exact solutions for macroscopic wavefunction ΨΨΨ demonstrate the emergence of redshiftredshiftredshift phase factor. For helical waveguides formed by phase-conjugated optical vortices with high angular momentum Lz=±ℓℏ∼±ℏ⋅103÷4L_z=\pm \ell \hbar \sim \pm \hbar \cdot 10^{3 ÷4}Lz​=±ℓℏ∼±ℏ⋅103÷4 one may expect the significant improvement of the phase-sensitivity δϕδϕδϕ by factor containing 2ℓ2 \ell2ℓ compared to the conventional nonsingular matter-wave interferometry.
Coupled nonlinear Schrödinger equations for paraxial optics with two circular polarizations of light in a defocusing Kerr medium with anomalous dispersion coincide in form with the Gross–Pitaevskii equations for a binary Bose—Einstein condensate (BEC) of cold atoms in the phase separation regime. In this case, the helical symmetry of an optical waveguide corresponds to rotation of the transverse potential confining the BEC. The “centrifugal force” considerably affects the propagation of a light wave in such a system. Numerical experiments for a waveguide with an elliptical cross section have revealed characteristic structures consisting of quantized vortices and domain walls between two polarizations, which have not been observed earlier in optics.
In this thesis, we will study the superfluidity of condensed atomic and photonic systems, through the manipulation of rotational states, such as vortices or persistent currents. We will study Bose-Einstein condensates both in the strongly-correlated regime, where models based on second quantization, like Bose-Hubbard model, will be required; and in weakly-interacting systems, where mean-field approximations will be accurate enough, and the system is described by means of the Gross-Pitaevskii equation.\n\n\t\t\t\t We will start with the analysis of the fundamental properties of Bose gases trapped in few-site lattices, such as the phase diagram, the condensed fractions and the entanglement. Concerning the phases, we will study the properties of the transitions between them and, in particular, their characteristic critical exponents.\n\n\t\t\t\t Afterwards, we will consider the sites of a lattice constituting a ring geometry and study the effect of manipulating the tunnelling rate between two of the wells. This kind of tunable link is called weak link, and we will analyze what happens in the mean-field approximation, in comparison with the strongly-correlated case. In both regimes we will observe that the weak link behaves as a key element in the system in order to generate superpositions of flow states. Moreover, in the mean-field case, we can identify an energy barrier that separates two current states (also known as winding number states), where solitonic states, i.e. states characterized by the presence of topological singularities, live. Such a barrier will be the origin of the appearance of a hysteresis cicle in processes of transfer between different winding number curves, called phase slips.\n\n\t\t\t\t After that, we will study two coherently-coupled components of a toroidally-trapped Bose-Einstein condensate. We will see that when we imprint a persistent current in one of the components, there is an angular momentum transfer between both components. This transfer can be identified as a phase slip event, and the tunability of the system allows it to behave as a robust qubit, due to the fact that states supported by currents are less fragile.\n\n\t\t\t\t In two-component condensates, it is possible to find a particular solitonic state called Josephson vortex. This state is characterized by a density depletion around a point with nonzero currents. Moreover, these states are energetically more favourable than dark soliton states, whose main difference with respect to Josephson vortices is the fact that dark solitons do not present currents. However, when spin-orbit coupling is added, dark soliton states are no longer possible, but Josephson vortices persist. In this thesis, we will see that these states decay through transversal excitations (i.e. snake instability), producing vortex-antivortex pairs, and their subsequent dynamical evolution depends on the initial orientation of the Josephson vortex.\n\n\t\t\t\t Finally, we will move to the field of polariton condensates. Polaritons are quasiparticles product of the coupling between photons and excitons (which are electron-hole excitations) in semiconductor microcavities. These particles can constitute an out-of-equilibrium (due to the short lifetime of polaritons) Bose-Einstein condensate described by the Gross-Pitaevskii-like equation for two components, because of the two polarization components inherent to the photonic nature of polaritons. The cavities where these condensates are created generate a spin-orbit coupling between the two polariton components, in such a way that current states with different orbital angular momentum are coupled. This yields to a phenomenon of spin-to-orbital angular momentum conversion that we will study in ring-trapped polariton condensates. At the end of this thesis, we will probe the superfluid properties of polariton condensates, by analyzing the response of the generated currents against the presence of disorder.
We discuss a possibility of a pinning of quantized matter wave vortices by optical vortices in specially arranged optical dipole traps. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum to support "antiferromagnet-like" matter waves. The separable Hamiltonian for matter waves is proposed which allows to factorize of the 3D - wavefunction exactly in a product of 1D - harmonic oscillator's ground state and 2D - vortex-antivortex wavefunction. The wavefunction's phase gradient field associated with the field of classical velocities via Madelung transformation forms labyrinth-like structure. The macroscopic wavefunction of periodically spaced BEC superfluid vortices appears to be less influenced by decoherence.
The field-theoretical renormalization-group techniques previously developed for the description of the mestastable phases of isotropic, homogeneous, ddd-dimensional systems, which (close to their critical temperature) can be described in terms of the Landau-Ginzburg-Wilson functional integral with a two-component order parameter, and applied to obtain the scaling form of the helicity modulus, defined as a measure of the free-energy increment associated with a metastable, helical twisting of the order parameter. The general scaling form of this quantity is determined even in the presence of an external helical field, for arbitrary helix pitch and temperature. In the case of vanishing external field, this quantity represents the superfluid density and is a function of the temperature and the superfluid velocity (which corresponds to the inverse of the helix pitch). In the limit of small velocities this expression exhibits the well-known Josephson asymptotic form ${\ensuremath{\rho}}_{s}\ensuremath{\sim}{({T}_{c}\ensuremath{-}T)}^{\ensuremath{\nu}(d\ensuremath{-}2)}={({T}_{c}\ensuremath{-}T)}^{2\ensuremath{\beta}\ensuremath{-}\ensuremath{\nu}\ensuremath{\eta}}$. An explicit $\ensuremath{\epsilon}=4\ensuremath{-}d$ expansion for the helicity modulus is presented in the case of arbitrary external field to the one-loop approximation.
A mechanism of a pinning of the quantized matter wave vortices by optical vortices in a specially arranged optical dipole traps is discussed. The vortex-antivortex optical arrays of rectangular symmetry are shown to transfer angular orbital momentum and form the “antiferromagnet”-like matter waves. The separable Hamiltonian for matter waves in pancake trapping geometry is proposed and 3D-wavefunction is factorized in a product of wavefunctions of the 1D harmonic oscillator and 2D vortex-antivortex quantum state. The 2D wavefunction’s phase gradient field associated via Madelung transform with the field of classical velocities forms labyrinth-like structure. The macroscopic quantum state composed of periodically spaced counter-rotating BEC superfluid vortices has zero angular momentum and nonzero rotational energy.