We study the nonequilibrium dynamics of an ultracold, nondegenerate dipolar gas of $^{164}\mathrm{Dy}$ atoms in a cylindrically symmetric harmonic trap. To do so, we investigate the normal modes and linear response of the gas when driven by means of periodic modulations to the trap axial frequency. We find that the resonant response of the gas depends strongly on the dipole alignment axis, owing to anisotropies in the differential cross section of the atoms. We employ the use of the method of averages as well as numerical Monte Carlo methods for our analysis. A striking result is that certain normal modes, termed ``melting modes,'' initiated in an anisotropic out-of-equilibrium configuration, relax to equilibrium without oscillating.We study the nonequilibrium dynamics of an ultracold, nondegenerate dipolar gas of $^{164}\mathrm{Dy}$ atoms in a cylindrically symmetric harmonic trap. To do so, we investigate the normal modes and linear response of the gas when driven by means of periodic modulations to the trap axial frequency. We find that the resonant response of the gas depends strongly on the dipole alignment axis, owing to anisotropies in the differential cross section of the atoms. We employ the use of the method of averages as well as numerical Monte Carlo methods for our analysis. A striking result is that certain normal modes, termed ``melting modes,'' initiated in an anisotropic out-of-equilibrium configuration, relax to equilibrium without oscillating.

arXiv:2006.13974Physical Review ASep 28, 202010 citations

Dipolar Bose gas in a highly anharmonic trap

Francesco Ancilotto, Flavio Toigo

By means of mean-field theory, we have studied the structure and excitation spectrum of a purely dipolar Bose gas in a pancake shaped trap where the confinement in the $x$ - $y$ plane is provided by a highly anharmonic potential, resulting in an almost uniform confinement in the plane. We show that the stable condensates are characterized by marked radially structured density profiles. The stability diagram is calculated by independently varying the strength of the interaction and the trap geometry. By computing the Bogoliubov excitation spectrum near the instability line we show that soft ``angular'' rotons are responsible for the collapse of the system. The free expansion of the cloud after the trap is released is also studied by means of time-dependent calculations, showing that a prolate cigar-shaped condensate is dynamically stabilized during the expansion, which would otherwise collapse. Dipolar condensates rotating with sufficiently high angular velocity show the formation of multiply quantized giant vortices, while the condensates acquire a ring-shaped form.By means of mean-field theory, we have studied the structure and excitation spectrum of a purely dipolar Bose gas in a pancake shaped trap where the confinement in the $x$-$y$ plane is provided by a highly anharmonic potential, resulting in an almost uniform confinement in the plane. We show that the stable condensates are characterized by marked radially structured density profiles. The stability diagram is calculated by independently varying the strength of the interaction and the trap geometry. By computing the Bogoliubov excitation spectrum near the instability line we show that soft ``angular'' rotons are responsible for the collapse of the system. The free expansion of the cloud after the trap is released is also studied by means of time-dependent calculations, showing that a prolate cigar-shaped condensate is dynamically stabilized during the expansion, which would otherwise collapse. Dipolar condensates rotating with sufficiently high angular velocity show the formation of multiply quantized giant vortices, while the condensates acquire a ring-shaped form.

arXiv:1401.2261Physical Review AFeb 14, 20147 citations

Damping of excitations in a dipolar Bose gas

Ryan Wilson, Stefan S. Natu

Bulletin of the American Physical SocietyMar 5, 20140 citations

The Excitation Spectrum for Weakly Interacting Bosons in a Trap

Philip Grech, Robert Seiringer

arXiv:1205.5259Communications in Mathematical PhysicsMay 21, 2013123 citations

Analysis of two and three dipolar bosons in a spherical harmonic trap

C. J. Bradly, Harry M. Quiney, A. Martin

As dipolar gases become more readily accessible in experiment there is a need to develop a comprehensive theoretical framework of the few-body physics of these systems. Here, we extend the coupled-pair approach developed for the unitary two-component Fermi gas to a few-body system of dipolar bosons in a spherical harmonic trap. The long range and anisotropy of the dipole-dipole interaction is handled by a flexible and efficient correlated Gaussian basis with stochastically variational optimization. Solutions of the two-body problem are used to calculate the eigenenergy spectrum and structural properties of three trapped bosonic dipoles. This demonstrates the efficiency and flexibility of the coupled-pair approach at dealing with systems with complex interactions.As dipolar gases become more readily accessible in experiment there is a need to develop a comprehensive theoretical framework of the few-body physics of these systems. Here, we extend the coupled-pair approach developed for the unitary two-component Fermi gas to a few-body system of dipolar bosons in a spherical harmonic trap. The long range and anisotropy of the dipole-dipole interaction is handled by a flexible and efficient correlated Gaussian basis with stochastically variational optimization. Solutions of the two-body problem are used to calculate the eigenenergy spectrum and structural properties of three trapped bosonic dipoles. This demonstrates the efficiency and flexibility of the coupled-pair approach at dealing with systems with complex interactions.

arXiv:1510.04757Physical Review AJan 12, 20160 citations

We study the nonequilibrium dynamics of an ultracold, nondegenerate dipolar gas of

^{164}\mathrm{Dy}

atoms in a cylindrically symmetric harmonic trap. To do so, we investigate the normal modes and linear response of the gas when driven by means of periodic modulations to the trap axial frequency. We find that the resonant response of the gas depends strongly on the dipole alignment axis, owing to anisotropies in the differential cross section of the atoms. We employ the use of the method of averages as well as numerical Monte Carlo methods for our analysis. A striking result is that certain normal modes, termed ``melting modes,'' initiated in an anisotropic out-of-equilibrium configuration, relax to equilibrium without oscillating.

By means of mean-field theory, we have studied the structure and excitation spectrum of a purely dipolar Bose gas in a pancake shaped trap where the confinement in the

x

y

plane is provided by a highly anharmonic potential, resulting in an almost uniform confinement in the plane. We show that the stable condensates are characterized by marked radially structured density profiles. The stability diagram is calculated by independently varying the strength of the interaction and the trap geometry. By computing the Bogoliubov excitation spectrum near the instability line we show that soft ``angular'' rotons are responsible for the collapse of the system. The free expansion of the cloud after the trap is released is also studied by means of time-dependent calculations, showing that a prolate cigar-shaped condensate is dynamically stabilized during the expansion, which would otherwise collapse. Dipolar condensates rotating with sufficiently high angular velocity show the formation of multiply quantized giant vortices, while the condensates acquire a ring-shaped form.