Online Learning of quantum processes
Learning properties of quantum processes is a fundamental task in physics. It is well known that full process tomography scales exponentially in the number of qubits. In this work, we consider online learning quantum processes in a mistake bounded model and prove exponentially improved bounds compared to the stronger notion of diamond norm learning. The problem can be modelled as an interactive game over any given number of rounds, T, between a learner and an adversary.
Tight-binding simulations of random alloy and strong spin-orbit effects in InAs/GaBiAs quantum dot molecules
Dissertation Committee Chair: Jay Deep Sau
Committee:
Garnett W. Bryant, Advisor/Co-Chair
Andrew M. Childs
Matthew F. Doty
Theodore L. Einstein
Michael Gullans
Realizing 2D topologically ordered states and their phase transitions in a programmable quantum processor.
Abstract: The search for exotic quantum phases of matter is a central theme in condensed matter physics. The advent of programmable quantum hardware provides an unprecedented access to novel quantum states and represents a new avenue for probing the exotic properties associated with topological order.. In this talk, I will discuss our progress in realization of topologically ordered ground states based on exact efficient quantum circuit representations.
Quantum quenches for enhancing qubit-based quantum noise spectroscopy
Qubit-based noise spectroscopy (QNS) techniques, where the dephasing of a probe qubit is exploited to study a system of interest, underlie some of the most common quantum sensing and noise characterization protocols. They have a variety of applications, ranging from designing effective quantum control protocols to investigating properties (phase transitions, thermodynamics, etc.) of quantum many-body systems.
Strong Coupling of Single Atoms in Optical Tweezers to a Fiber Cavity: Novel approaches to Cavity-Mediated Entanglement
Abstract: Neutral atom quantum processors can greatly benefit from integration with optical cavities. These optical interfaces can be used for fast readout for real time error detection and as a quantum networking node to entangle distant quantum processors. Here we present one candidate for such integration: a Fabry-Perot Fiber Cavity (FPFC). This system is compatible with optical tweezer arrays and enables strong coupling of multiple atoms with a single cavity mode.
Topological Defects and Textures in Two-Dimensional Quantum Orders: Interplay of Symmetry Breaking and Topological Order
The two most prevalent classes of ordered states in quantum materials are those arising from spontaneous symmetry breaking (SSB) and from topological order. However, a systematic study for their coexistence in interacting systems is still lacking. In this talk, I will discuss how the topological configuration in order parameter spaces from SSB (classical topology) interplays with the symmetry protected/enriched topological orders (quantum topology) in two spatial dimensions (2d). Three examples of such systems will be given.
Fault-tolerant hyperbolic Floquet quantum error correcting codes
A central goal in quantum error correction is to reduce the overhead of fault-tolerant quantum computing by increasing noise thresholds and reducing the number of physical qubits required to sustain a logical qubit.
The Quantum Internet
Many organized efforts across the world are racing to realize the "Quantum Internet" -- the internet of the future that is upgraded to provide an additional service: that of reliably transmitting qubits between distant users. Just like the internet's classical data communications service, the quantum communications service must reliably support many user groups, and support diverse and dynamic applications---each with its unique requirements on the quality of service for transmission of qubits, e.g., rate, latency, fidelity etc.