Seth T. Rittenhouse

The hyperspherical four-fermion problem

The problem of a few interacting fermions in quantum physics has sparked intense interest, particularly in recent years owing to connections with the behaviour of superconductors, fermionic superfluids and finite nuclei. This review addresses recent developments in the theoretical description of four fermions having finite-range interactions, stressing insights that have emerged from a hyperspherical coordinate perspective. The subject is complicated, so we have included many detailed formulae that will hopefully make these methods accessible to others interested in using them. The universality regime, where the dominant length scale in the problem is the two-body scattering length, is particularly stressed, including its implications for the famous BCS–BEC crossover problem. Derivations and relevant formulae are also included for the calculation of challenging few-body processes such as recombination.

A Homonuclear Molecule with a Permanent Electric Dipole Moment

Two rubidium atoms, one in its ground state and the other with a highly excited electron, form a metastable polar molecule. Permanent electric dipole moments in molecules require a breaking of parity symmetry. Conventionally, this symmetry breaking relies on the presence of heteronuclear constituents. We report the observation of a permanent electric dipole moment in a homonuclear molecule in which the binding is based on asymmetric electronic excitation between the atoms. These exotic molecules consist of a ground-state rubidium (Rb) atom bound inside a second Rb atom electronically excited to a high-lying Rydberg state. Detailed calculations predict appreciable dipole moments on the order of 1 Debye, in excellent agreement with the observations.

Observation of blueshifted ultralong-range Cs2 Rydberg molecules.

We observe ultralong-range blueshifted

General Theoretical Description of N-Body Recombination

{\mathrm{Cs}}_{2}

Production of trilobite Rydberg molecule dimers with kilo-Debye permanent electric dipole moments

molecular states near

Ultracold giant polyatomic Rydberg molecules: coherent control of molecular orientation.

n{s}_{1/2}

Three body recombination of ultracold dipoles to weakly bound dimers.

Rydberg states in an optical dipole trap, where

First-Order Phase Transitions in Optical Lattices with Tunable Three-Body Onsite Interaction

31\ensuremath{\le}n\ensuremath{\le}34

Green's Functions and the Adiabatic Hyperspherical Method

. The accidental near degeneracy of

Dimer-dimer collisions at finite energies in two-component Fermi gases

(n\ensuremath{-}4)l