Science of Deep Learning: From Initialization to Emergent Structures
Dissertation Committee Chair: Maissam Barkeshli
Committee:
Andrey Gromov (advisor)
Victor Albert
Tom Goldstein
Christopher Jarzynski (Dean’s representative)
Levitated Optomechanics for Precision Searches of New Physics.
Optomechanical detectors offer a highly sensitive method for measuring weak forces. By optically trapping these systems in high vacuum, one can drastically reduce environmental noise and achieve exquisite control over the detector’s center-of-mass motion, rotational degrees of freedom, and physical characteristics such as charge states. This level of isolation enables the detector’s noise to reach the quantum measurement regime, where the dominant noise source is the measurement process itself.
New JQI Fellow Wants to Build an Error-Creating Quantum Computer
In her new lab, Alaina Green is making a quantum computer that is better at intentionally creating quantum errors that can be systematically studied.
The Complexity of Thermalization in Finite Quantum Systems
Abstract: Whether or not a physical system will thermalize from an initial state has been a key question in modern condensed matter physics. Closely related questions are determining whether observables in these systems relax to stationary values, and what those values are. Using tools from computational complexity theory, we demonstrate that given a Hamiltonian on a finite-sized system, determining whether or not it thermalizes or relaxes to a given stationary value is computationally intractable, even for a quantum computer.
Researchers Play a Microscopic Game of Darts with Melted Gold
Lasers helped UMD researchers hone their aim in a microscopic game of darts played to recover gold nanoparticles from levitation experiments.
Topological stabilizer models on continuous variables
Abstract: In [1] we constructed a family of two-dimensional topological stabilizer codes on continuous variable (CV) degrees of freedom, which generalize homological rotor codes and the toric-GKP code. Our topological codes are built using the concept of boson condensation -- we start from a parent stabilizer code based on an R gauge theory and condense various bosonic excitations.
Continuously tunable surface code logicals via syndrome-adaptive transversal operations
Abstract: A set of universal fault-tolerant logical gates in quantum error correcting codes is necessary for quantum computing. Transversal operations applied independently on each qubit in a code block are naturally fault-tolerant and easy to implement, but the Eastin-Knill theorem states that the resulting discrete gate set cannot be universal. Circumventing this requires complex protocols such as magic state distillation, code switching, etc. Surface code error correction has been demonstrated on several experimental platforms.