JQI

Controlling the functional properties of quantum materials with light has emerged as a frontier of condensed matter physics, leading to discoveries of various light-induced phases of matter, such as superconductivity, ferroelectricity, magnetism, and charge density waves. However, in most cases, the photoinduced phases return to equilibrium on ultrafast timescales after the light is turned off, limiting their practical applications.

We have recently created the first Bose-Einstein condensate (BEC) of dipolar
molecules [1-3]. We efficiently cool sodium-cesium molecules from 700 nK to less
than 10 nK, deep into the quantum degenerate regime. The lifetime of the molecular
BEC is longer than one second, reaching a level of stability similar to ultracold atomic
gases. A cornerstone of this advance is double microwave shielding, a novel
technique that gives us control over intermolecular interactions and reduces inelastic

Abstract: Electron spins in semiconductor quantum dots typically interact with many nuclear spins in their semiconductor environments, realizing a manifestation of the central spin problem. The central spin problem is a widely studied model of decoherence and is predicted to exhibit a rich variety of interesting and useful phenomena, only some of which have been observed. In this talk, I will discuss a series of experiments exploring these dynamics in silicon quantum dots.

Laser-cooled atoms in a high-finesse optical cavity are a powerful tool for quantum simulation and quantum sensing.  The optical-cavity enhances the light-matter interaction, mediating effective atom-atom interactions and probing of the quantum state below the mean-field level.  In this talk, I will provide an overview of my group’s recent work in this area.  We perform cavity-enhanced quantum non-demolition measurements to create highly-entangled states [1], with the first realization of a squeezed matter wave interferometer for inertial sensing [2] and a squeezin

Abstract:  Inhomogeneities are common in quantum materials and can radically impact their fundamental as well as functional properties. In this talk, I will discuss femtosecond resolved nanoscale snapshots of an insulator to metal phase transition in a Vanadium Dioxide thin film. Inhomogeneous development of metallicity is observed at nanometer length scales and picosecond timescales. Movies of the phase transition are found to correlate with heterogeneous features observed in the steady state including grain boundaries and twin domains.

Abstract: In recent years, the use of Gottesman-Kitaev-Preskill (GKP) Codes to  implement fault-tolerant quantum computation has gained significant traction and evidence for their experimental utility has steadily grown.  But what does it even mean for quantum computation with the GKP code to be fault tolerant?  In this talk, we discuss the structure of logical Clifford gates for the GKP code and how their understanding leads to a classification of the space of all GKP Codes.

Abstract: In this work we present fast constructions for the quantum Fourier transform and quantum integer multiplication, using few ancilla qubits compared to the size of the input. For the approximate QFT we achieve depth O(log n) using only n + O(n / log n) total qubits, by applying a new technique we call "optimistic quantum circuits." To our knowledge this is the first circuit for the AQFT with space-time product O(n log n), matching a known lower bound. For multiplication, we construct circuits that use no ancilla qubits and only O(n^(1+eps)) gates (for arbitrary eps>0).

Abstract: Light is quantum. Hence, quantifying and attaining fundamental limits of transmitting, processing and extracting information encoded in light must use quantum analyses. This talk is aimed at elucidating this using principles from information and estimation theories, and quantum modeling of light. We will discuss nuances of “informationally optimal” measurements on so-called Gaussian states of light in the contexts of a few different metrics.