Adam Savage visits RbK!
Adam Savage, of Mythbusters fame, gave the NIST colloquium today and visited the RbK lab! Pictured (left to right) are Alina, Ian, Edvinas, Emmanuel and Adam.
Author: Ian Spielman
Observation of Anisotropic Superfluid Density in an Artificial Crystal
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 »
Weak-measurement-induced heating in Bose-Einstein condensates
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 »
Feedback-cooled Bose-Einstein condensation: Near and far from equilibrium
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 »
A 20 A bipolar current source with 140 μA noise over 100 kHz bandwidth
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 »
Direct calibration of laser intensity via Ramsey interferometry for cold atom imaging
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 »
Quantum back-action limits in dispersively measured Bose-Einstein condensates
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 »
Interference induced anisotropy in a two-dimensional dark state optical lattice
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 »
Topological charge pumping with subwavelength Raman lattices
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 »
JQI writeup: Twisting Up Atoms Through Space and Time
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 »