655 research outputs found
Bryn Mawr College
Photographs from the Bryn Mawr College Archives, the Alumnae Bulletin, and the Office of Public Informationhttps://repository.brynmawr.edu/bmc_books/1001/thumbnail.jp
Scattering of two particles in a one-dimensional lattice
This study concerns the two-body scattering of particles in a one-dimensional periodic potential. A convenient ansatz allows for the separation of center-of-mass and relative motion, leading to a discrete Schrodinger equation in the relative motion that resembles a tight-binding model. A lattice Green's function is used to develop the Lippmann-Schwinger equation, and ultimately derive a multiband scattering K matrix which is described in detail in the two-band approximation. Two distinct scattering lengths are defined according to the limits of zero relative quasimomentum at the top and bottom edges of the two-body collision band. Scattering resonances occur in the collision band when the energy is coincident with a bound state attached to another higher or lower band. Notably, repulsive on-site interactions in an energetically closed lower band lead to collision resonances in an excited band
Observation of blue-shifted ultralong-range Cs Rydberg molecules
We observe ultralong-range blue-shifted Cs molecular states near
Rydberg states in an optical dipole trap, where .
The accidental near degeneracy of and Rydberg states for in
Cs, due to the small fractional quantum defect, leads to non-adiabatic
coupling among these states, producing potential wells above the
thresholds. Two important consequences of admixing high angular momentum states
with states are the formation of large permanent dipole moments, Debye, and accessibility of these states via two-photon association.
The observed states are in excellent agreement with theory. Both projections of
the total angular momentum on the internuclear axis are visible in the
experiment
A Dielectric Superfluid of Polar Molecules
We show that, under achievable experimental conditions, a Bose-Einstein
condensate (BEC) of polar molecules can exhibit dielectric character. In
particular, we derive a set of self-consistent mean-field equations that couple
the condensate density to its electric dipole field, leading to the emergence
of polarization modes that are coupled to the rich quasiparticle spectrum of
the condensate. While the usual roton instability is suppressed in this system,
the coupling can give rise to a phonon-like instability that is characteristic
of a dielectric material with a negative static dielectric function.Comment: Version published in New Journal of Physics, 11+ pages, 4 figure
Engineering chiral spin interactions with Rydberg atoms
We propose to simulate the anisotropic and chiral Dzyaloshinskii-Moriya (DM)
interaction with Rydberg atom arrays. The DM Hamiltonian is engineered in a
one-dimensional optical lattice or trap array with effective long-range Rydberg
spins, interacting indirectly via a mobile mediator Rydberg atom. A host of XXZ
and DM Hamiltonians can be simulated with out-of-phase sign periodic coupling
strengths; for initial states in a stationary condensate, the DM interaction
vanishes. This theory allows for determination of the DM interaction (DMI)
vector components from first principles. The inherent anisotropy of the
Rydberg-Rydberg interactions, facilitates the DMI coupling to be tuned so as to
be comparable to the XXZ interaction. Our results make plausible the formation
of non-trivial topological spin textures with Rydberg atom arrays.Comment: 4 pages, 2 figure
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