Measurement. Science is rooted in measurement: it is from measurements, as unified by theory, that understanding is born. Our comprehension of the universe is therefore bounded by our ability to observe and shaped by human creativity.  Scientific progress is driven by the identification of new physical systems and measurement techniques, leading to new conceptual understanding. Our experiments use systems of ultracold neutral atoms, quantum gases, that make quantum physics manifest in the laboratory. Many properties of these systems can be understood in the intellectual context of many-body physics which describes systems from the commonplace such as crystals, fluids, and semiconductors, to the extreme such as superconductors, quantum Hall systems, and neutron stars.  Many-body physics asks how the properties of individual components — atoms, electrons, nucleons — give rise to the observed macroscopic phenomena.

Ultracold atoms are a very different sort of system than conventional materials, composed of a few hundred to a few hundred million atoms, with densities ranging from 1012 cm-3 to 1015 cm-3, and at temperatures from below 1 nK to a couple uK.  These atomic systems are unique in the simplicity of their underlying Hamiltonian along with a singular capacity for controlling and engineering their quantum degrees of freedom.

Our experiments — inspired by the on-going theory efforts of our collaborators world-wide — take place on three distinct apparatuses: RbK, focusing on artificial gauge fields for atomic Bose and Fermi gases; RbChip, creating spin-dependent forces without light; and RbLi, designing long range interactions mediated by particle exchange.


Brownian motion of solitons in a Bose–Einstein condensate

Solitons, spatially localized, mobile excitations resulting from an interplay between nonlinearity and dispersion, are ubiquitous in physical systems from water channels and oceans to optical fibers and Bose–Einstein condensates (BECs). From our pulse throbbing at our wrists to rapidly moving

Posted in Group News, Papers Published, RbK

Semisynthetic zigzag optical lattice for ultracold bosons

We propose a cold-atom realization of a zigzag ladder. The two legs of the ladder correspond to a “synthetic” dimension given by two internal (spin) states of the atoms, so that tunneling between them can be realized as a laser-assisted

Posted in Group News, Papers Published, Theory

Real-space mean-field theory of a spin-1 Bose gas in synthetic dimensions

The internal degrees of freedom provided by ultracold atoms provide a route for realizing higher dimensional physics in systems with limited spatial dimensions. Nonspatial degrees of freedom in these systems are dubbed “synthetic dimensions.” This connection is useful from an

Posted in Group News, Theory

21 Rules of Thumb for Shipping Great Software on Time: applied to physics research

12 years ago when I was a still graduate student, my wife — then a database developer — sent me a small article titled “21 Rules of Thumb for Shipping Great Software on Time” that were applied in managing the

Posted in Group News

Vortex nucleation in a Bose–Einstein condensate: from the inside out

We observed a new mechanism for vortex nucleation in Bose–Einstein condensates (BECs) subject to synthetic magnetic fields. We made use of a strong synthetic magnetic field initially localized between a pair of merging BECs to rapidly create vortices in the

Posted in Atomtronics, Group News, Papers Published, RbLi

Dr. Lauren M. Aycock defended her thesis today.

Lauren defended her thesis titled “Topological excitations in a Bose gas & sexual harassment reported by undergraduate physicists” today to a bumper audience in Ithaca.  And it rocked!

Posted in Group News, Personnel, RbK, Uncategorized

Tutorial: Synthetic gauge potentials for ultracold neutral atoms

Synthetic gauge fields for ultracold neutral atoms—engineered using the interaction between laser fields and the atoms’ internal ‘spin’ degrees of freedom—provide promising techniques for generating the large (synthetic) magnetic fields required to reach the fractional quantum Hall (FQH) limit in

Posted in Group News, Papers Published, RbK, Theory

Geometrical Pumping with a Bose-Einstein Condensate

We realized a quantum geometric “charge” pump for a Bose-Einstein condensate (BEC) in the lowest Bloch band of a novel bipartite magnetic lattice [JQI writeup]. Topological charge pumps in filled bands yield quantized pumping set by the global—topological—properties of the

Posted in Atomtronics, Group News, Papers Published, RbK

Rockville Science day with Troop 1097

The boys of Boy Scout troop 1097 helped Ian out and presented experiments ranging from magnetism to superconductivity at the 2016 Rockville Science day! In the photo, Michael and Camden are explaining an electromagnet and induced currents!

Posted in Group News

Celebration of: Magnetic phases of spin-1 spin–orbit-coupled Bose gases

The UMD team got together to celebrate our recent paper “Magnetic phases of spin-1 spin–orbit-coupled Bose gases;” for some reason we went to Town Hall a long-time College Park dive bar. Times were good! Ana, Erin and Dimi were in

Posted in Group News, RbLi