JQI

Abstract: Fundamental forces of nature are described by gauge theories, and the interactions of matter with gauge fields lead to intriguing phenomena like the confinement of quarks in quantum chromodynamics. Separating a confined quark-anti-quark pair incurs an energy cost that grows linearly with their separation, eventually leading to the production of additional particles by an effect that is called string-breaking. In this talk, I will discuss how similar phenomenology can be probed using Rydberg atom arrays.

Abstract: Vortices appear in optics as phase twists in the electromagnetic field resulting from light-matter interactions. Quantum vortices, characterized by phase singularities in the wavefunction, are typically associated with strongly interacting many-particle systems. However, the emergence of vortices through the effective interaction of light with itself, a phenomenon requiring strong optical nonlinearity, was previously limited to the classical regime until recent advancements. 

Abstract: Irreversible quantum computation requires thermodynamic work. In principle, one can often evade work costs by implementing reversible transformations. In practice, complexity---the difficulty of realizing a quantum process---poses an obstacle: a realistic agent can perform only a limited number of gates and so not every reversible transformation. Hence an agent, if unable to complete a task unitarily, may expend work on an irreversible process, such as erasure, to finish the job.

Dissertation Committee Chair: Mohammad Hafezi

Committee: 

Jay Deep Sau

You Zhou

Aaron Sternbach

Ian B. Spielman

Christopher Jarzynski (Dean’s representative)

Dissertation Committee Chair: Christopher J. Lobb

Committee:

Jacob M. Taylor

Victor M. Galitski

Saikat Guha

Alicia J. Kollar

Abstract: There is a deep connection between quantum error correction and phases of matter for spatially local codes in finite dimensions.  I will show how this analogy extends to more general settings: quantum codes with check soundness are absolutely stable phases of matter.  These codes include constant-rate quantum low-density parity-check codes, which shows that the third law of thermodynamics is false: there exist absolutely stable phases of matter with constant entropy density at zero temperature.

Abstract: Inspired by natural cooling processes, dissipation has become a promising approach for preparing low-energy states of quantum systems. However, the potential of dissipative protocols remains unclear beyond certain commuting Hamiltonians.

Abstract: Experimental control over the strength and angular dependence of interactions between atoms is a key capability for advancing quantum technologies. Here, we use microwave dressing to manipulate and enhance Rydberg-Rydberg interactions in an atomic ensemble. By resonantly coupling opposite parity Rydberg states, we create eigenstates with first-order dipole-dipole interactions. We study the modification of the interactions by measuring the statistics of the light retrieved from the ensemble.

Dissertation Committee Chair: Maissam Barkeshli

Committee: 

Andrey Gromov (advisor)

Victor Albert

Tom Goldstein

Christopher Jarzynski (Dean’s representative)