Universality of Dicke superradiance in atomic arrays
Abstract: Tightly packed ordered arrays of atoms exhibit remarkable collective optical properties, as dissipation in the form of photon emission is correlated. In this talk, I will discuss the many-body out-of-equilibrium physics of atomic arrays, and focus on the problem of Dicke superradiance, where a collection of excited atoms synchronizes as they decay, emitting a short and intense pulse of light. Superradiance remains an open problem in extended systems due to the exponential growth of complexity with atom number.
Squeezed Ground States in a Spin-1 Bose-Einstein Condensate
Abstract: We find a fast non-adiabatic protocol for the creation of spin squeezed ground states in a spin-1 Bose condensate and experimentally generate those states near the quantum critical point between the polar and ferromagnetic quantum phases of the interacting spin ensemble. The method consists of a pair of controlled quenches of an external magnetic field, which has the same leading order dependence for the total time as the quantum optimal control method but is simpler and realizable.
The Emerging Quantum Industry
An industry is emerging to develop practical applications of the quantum computing, communication and networking concepts that have emerged during the past 25 years. We will hear of opportunities and challenges in this field from two industry leaders:
EXCITED STATES IN MONOLAYER TRANSITION METAL DICHALCOGENIDES
Dissertation Committee Chair: Mohammad Hafezi
Committee:
Sunil Mittal
Glenn Solomon
Ichiro Takeuchi
You Zhou
Harnessing the ultimate quantum-enhanced sensitivity in distributed quantum sensing with squeezed light
Abstract: Distributed quantum sensing is an exciting emerging research field aimed at harnessing quantum resources to achieve quantum-enhanced sensitivity in the estimation of single or multiple parameters, including temperature, electromagnetic and gravitational fields, distributed in a given quantum network. In particular, squeezing is a well established resource given its feasibility and robustness to decoherence with respect to entangled sources.
Simulating the Schwinger Model and Testing Symmetry Protection with Trapped Ions
Gauge theory is a powerful theoretical framework for understanding the fundamental forces in the standard model. Simulating the real time dynamics of gauge theory, especially in the strong coupling regime, is a challenging classical problem. Quantum computers offer a solution to this problem by taking advantage of the intrinsic quantum nature of the systems. The Schwinger model, that is the 1+1 dimensional U(1) gauge theory coupled to fermions, has served as a testbed for different methods of quantum simulation.
Neural-Network Decoders for Measurement Induced Phase Transitions
Monitored random unitary circuits with intermittent measurements can host a phase transition between a pure and a mixed phase with different entanglement entropy behaviors with the system size. Recently, it was demonstrated that these phase transitions can be locally probed via entangling reference qubits to the quantum circuit and studying the purification dynamics of the reference qubits. After disentangling from the circuit, the state of the reference qubit can be determined according to the measurement outcomes of the qubits in the circuit.
Using a trapped ion quantum computer to simulate NMR spectra
Nuclear magnetic resonance (NMR) spectroscopy is a useful tool in understanding molecular composition and dynamics, but simulating NMR spectra of large molecules becomes intractable on classical computers as the spin correlations in these systems can grow exponentially with molecule size. In contrast, quantum computers are well suited to simulate NMR spectra of molecules, particularly zero- to ultralow field (ZULF) NMR where the spin-spin interactions in the molecules dominate.
Autonomous quantum error correction of a grid state qubit
Quantum error correction is expected to play an important role in the realization of large-scale quantum computers. At the lowest level, it takes advantage of embedding qubits in a larger Hilbert space, giving redundancy which allows measurements which preserve logical information while revealing the presence of errors. While many codes rely on multiple physical systems, Bosonic codes make use of the higher dimensional Hilbert space of a single harmonic oscillator mode.
Clustering of steady-state correlations in open systems with long-range interactions
Lieb-Robinson bounds are powerful analytical tools for constraining the dynamic and static properties of non-relativistic quantum systems. Recently, a complete picture for closed systems that evolve unitarily in time has been achieved. In experimental systems, however, interactions with the environment cannot generally be ignored, and the extension of Lieb-Robinson bounds to dissipative systems which evolve non-unitarily in time remains an open challenge.