Much of our knowledge of quantum systems is encapsulated in the expectation value of Hermitian operators, experimentally obtained by averaging projective measurements. However, dynamical properties are often described by products of operators evaluated at different times; such observables cannot be …
Dynamical structure factor from weak measurements Read more »
Geometrical frustration and long-range couplings are key contributors to create quantum phases with different properties throughout physics. We propose a scheme where both ingredients naturally emerge in a Raman induced subwavelength lattice. We first demonstrate that Raman-coupled multicomponent quantum gases …
We investigated turbulence in 2D atomic Bose-Einstein condensates (BECs) using a minimally destructive, impurity injection technique analogous to particle image velocimetry in conventional fluids. Our approach transfers small regions of the BEC into a different hyperfine state and tracks their …
Kolmogorov Scaling in Turbulent 2D Bose-Einstein Condensates Read more »
Weak measurement enables the extraction of targeted information from a quantum system while minimizing decoherence due to measurement backaction. However, in many-body quantum systems, backaction can have unexpected effects on wave-function collapse. We theoretically study a minimal many-particle model consisting …
Measurement resolution enhanced coherence for lattice fermions Read more »
We consider solitary wave excitations above the ground state of 𝐹=1 spin-orbit-coupled Bose-Einstein condensates (SOBECs). The low-energy properties of SOBECs in any of the three branches of the single-particle dispersion relation can be described by suitable scalar nonlinear Schrödinger (NLS) equations which we …
Stationary solitary waves in F=1 spin-orbit-coupled Bose-Einstein condensates Read more »
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 »