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 »
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 »
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 »
Quantum states can acquire a geometric phase called the Berry phase after adiabatically traversing a closed loop, which depends on the path not the rate of motion. The Berry phase is analogous to the Aharonov–Bohm phase derived from the electromagnetic …
Wilson loop and Wilczek-Zee phase from a non-Abelian gauge field Read more »
On this day, November 2, 2020, Yuchen Yue remotely defended his thesis. Congratulations Yuchen!
Anderson localization is a single-particle localization phenomena in disordered media that is accompanied by an absence of diffusion. Spin-orbit coupling (SOC) describes an interaction between a particle’s spin and its momentum that directly affects its energy dispersion, for example, creating …
Enhanced transport of spin-orbit-coupled Bose gases in disordered potentials Read more »
On this day, April 6, 2020, Francisco Salces-Carcoba has (remotely) become Dr. ! Congratulations Paco!
Spin-orbit-coupled Bose-Einstein condensates (SOBECs) exhibit two new phases of matter, now known as the stripe and plane-wave phases. When two interacting spin components of a SOBEC spatially overlap, density modulations with periodicity given by the spin-orbit coupling strength appear. In …
Spatial Coherence of Spin-Orbit-Coupled Bose Gases Read more »
We trap individual 1D Bose gases and obtain the associated equation of state by combining calibrated confining potentials with in situ density profiles. Our observations agree well with the exact Yang–Yang 1D thermodynamic solutions under the local density approximation. We find that …
Equations of state from individual one-dimensional Bose gases Read more »