Spring 2025

There has been increasing interest in classifying mixed quantum states with topological order, particularly in understanding when states connected by local noise channels remain in the same topological phase. This framework has recently been applied to topological quantum error-correcting codes, where the use of the Petz recovery map has shown that phase transitions in mixed states align with the decodability threshold of these codes. Motivated by these insights, we introduce a scalable, parallelized, quasi-local decoder that achieves near-optimal performance for topological codes.

Abstract: There has been increasing interest in classifying mixed quantum states with topological order, particularly in understanding when states connected by local noise channels remain in the same topological phase. This framework has recently been applied to topological quantum error-correcting codes, where the use of the Petz recovery map has shown that phase transitions in mixed states align with the decodability threshold of these codes.

Building large-scale modular quantum computers and quantum networks require high fidelity, high efficiency, and long lifetime quantum memories [1]. Quantum memories are proposed to increase photon-mediatated matter-qubit entanglment rates by synchronizing photon interference between network nodes [2]. Hybrid quantum networking leverages trapped ions’ high fidelity operations and neutral-atoms’ single photon manipulation for increased entanglement rates over single-species quantum networks [3-8].

Abstract: Building large-scale modular quantum computers and quantum networks require high fidelity, high efficiency, and long lifetime quantum memories [1]. Quantum memories are proposed to increase photon-mediatated matter-qubit entanglment rates by synchronizing photon interference between network nodes [2].

Abstract: Many-body fermionic systems can be simulated in a hardware-efficient manner using a fermionic quantum processor. Neutral atoms trapped in optical potentials can realize such processors, where non-local fermionic statistics are guaranteed at the hardware level. Implementing quantum error correction in this setup is however challenging, due to the atom-number superselection present in atomic systems, that is, the impossibility of creating coherent superpositions of different particle numbers.

Abstract: In this talk, we will mainly focus on noisy quantum trees: at each node of a tree, a received qubit unitarily interacts with fresh ancilla qubits, after which each qubit is sent through a noisy channel to a different node in the next level. Therefore, as the tree depth grows, there is a competition between the irreversible effect of noise and the protection against such noise achieved by delocalization of information.

In this talk, we will mainly focus on noisy quantum trees: at each node of a tree, a received qubit unitarily interacts with fresh ancilla qubits, after which each qubit is sent through a noisy channel to a different node in the next level. Therefore, as the tree depth grows, there is a competition between the irreversible effect of noise and the protection against such noise achieved by delocalization of information.

Many-body fermionic systems can be simulated in a hardware-efficient manner using a fermionic quantum processor. Neutral atoms trapped in optical potentials can realize such processors, where non-local fermionic statistics are guaranteed at the hardware level. Implementing quantum error correction in this setup is however challenging, due to the atom-number superselection present in atomic systems, that is, the impossibility of creating coherent superpositions of different particle numbers.

Dissertation Committee Chair: Maissam Barkeshli

Committee: 

Victor Galitski

Victor Yakovenko

Avik Dutt

Jonathan Rosenberg

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.