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
Abstract: 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.
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. In this talk, I will introduce a potential path towards this goal based on a family of dynamically generated quantum error correcting codes that we call “hyperbolic Floquet codes.” These codes are defined by a specific sequence of non-commuting two-body measurements arranged periodically in time that stabilize a topological code on a hyperbolic manifold with negative curvature.
Topological Defects and Textures in Two-Dimensional Quantum Orders: Interplay of Symmetry Breaking and Topological Order
Abstract: 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.
The Quantum Internet
Booz Allen Hamilton Colloquium
New directions in quantum state learning and testing
Abstract: I will talk about:
. New efficient algorithms for quantum state tomography (the quantum analogue of estimating a probability distribution).
. Why you should care about the difference between total variation distance and Hellinger distance and KL divergence and chi-squared divergence.
. Quantum-inspired improvements to the classical problem of independence testing.
Includes joint work with Steven T. Flammia (Amazon)
Recent progress in Hamiltonian learning
Abstract: In the last few years, a number of works have proposed and improved provably efficient algorithms for learning the Hamiltonian from real-time dynamics. In this talk, I will first provide an overview of these developments, and then discuss how the Heisenberg limit, the fundamental precision limit imposed by quantum mechanics, can be reached for this task. I will show that reaching the Heisenberg limit requires techniques that are fundamentally different from previous ones.
Quantum Advantage Without Speed-Ups
Abstract: Quantum cryptography leverages unique features of quantum mechanics in order to construct cryptographic primitives which are oftentimes impossible for digital computers. Cryptographic applications of quantum computers therefore have the potential for useful quantum advantage – entirely without computational speed-ups. In this talk, I will focus on two fundamental questions: First, is it possible to certify that private data has been deleted? And second, is it possible to revoke a cryptographic key?