We experimentally and theoretically investigate the anisotropic speed of sound of an atomic superfluid (SF) Bose-Einstein condensate in a 1D optical lattice. Because the speed of sound derives from the SF density, this implies that the SF density is itself …
Observation of Anisotropic Superfluid Density in an Artificial Crystal Read more »
Ultracold atoms are an ideal platform for understanding system-reservoir dynamics of many-body systems. Here, we study quantum back-action in atomic Bose-Einstein condensates, weakly interacting with a far-from resonant, i.e., dispersively interacting, probe laser beam. The light scattered by the atoms …
Weak-measurement-induced heating in Bose-Einstein condensates Read more »
Continuously measured interacting quantum systems almost invariably heat, causing loss of quantum coherence. Here, we study Bose-Einstein condensates (BECs) subject to repeated weak measurement of the atomic density and describe several protocols for generating a feedback signal designed to remove …
Feedback-cooled Bose-Einstein condensation: Near and far from equilibrium Read more »
The precise control of direct current (dc) magnetic fields is crucial in a wide range of experimental platforms, from ultracold quantum gases and nuclear magnetic resonance to precision measurements. In each of these cases, the Zeeman effect causes quantum states …
A 20 A bipolar current source with 140 μA noise over 100 kHz bandwidth Read more »
A majority of ultracold atom experiments utilize resonant absorption imaging techniques to obtain the atomic density. To make well-controlled quantitative measurements, the optical intensity of the probe beam must be precisely calibrated in units of the atomic saturation intensity Isat. In …
Direct calibration of laser intensity via Ramsey interferometry for cold atom imaging Read more »
A fundamental tenet of quantum mechanics is that measurements change a system’s wavefunction to that most consistent with the measurement outcome, even if no observer is present. Weak measurements produce only limited information about the system, and as a result …
Quantum back-action limits in dispersively measured Bose-Einstein condensates Read more »
We describe a two-dimensional optical lattice for ultracold atoms with spatial features below the diffraction limit created by a bichromatic optical standing wave. At every point in space these fields couple the internal atomic states in a three-level Lambda coupling …
Interference induced anisotropy in a two-dimensional dark state optical lattice Read more »
Recent experiments demonstrated deeply subwavelength lattices using atoms with N internal states Raman coupled with lasers of wavelength λ. The resulting unit cell was λ/2N in extent, an N-fold reduction compared to the usual λ/2 periodicity of an optical lattice. For resonant Raman coupling, this lattice consists of N independent …
Topological charge pumping with subwavelength Raman lattices Read more »
Fab science communicator and group alum Dina Genkina has done a great writeup of our recent results! Dynamically Induced Symmetry Breaking and Out-of-Equilibrium Topology in a 1D Quantum System; G. H. Reid, M. Lu, A. R. Fritsch, A. M. Piñeiro, …
JQI writeup: Twisting Up Atoms Through Space and Time Read more »
We establish a dataset of over 1.6 x 10^4 experimental images of Bose–Einstein condensates containing solitonic excitations to enable machine learning (ML) for many-body physics research. About 33% of this dataset has manually assigned and carefully curated labels. The remainder …
Dark solitons in Bose–Einstein condensates: a dataset for many-body physics research Read more »