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Welcome to QI/QC Lab!

In Summer 2023, group meetings will take place at 2 PM Pacific Time on Wednesdays in Academic Surge 2022 (for in-person attendees) or on Zoom (for remote attendees, see group Slack for link). All regular meetings are recorded and uploaded to our meeting archive on Box and previously on Dropbox.

Members

Name Institution Program Research interests
Isaac Kim UC Davis PI, CS/Physics
Ian Lim UC Davis PhD, Physics (2019-present) Field theory, Entanglement entropy, Holography, QEC
Guangqi Zhao USYD PhD, Physics (2021 - Present) Quantum Error Correction
Zijian Song UC Davis PhD, Physics (2020-present) Quantum Information, Quantum Many Body Systems
Michael Ragone UC Davis PhD, Math (2018-present) Quantum Many Body Systems, Quantum Information
Sanchayan Dutta UC Davis PhD, Math (2021-present) Quantum Error Correction, Algebraic and Geometric Topology, Operator Algebras, Computational Complexity
Arkin Tikku USYD PhD
Jintae Kim SKKU Integrated Master & PhD, Physics (2018 - present) Quantum Error Correction, Condensed Matter Theory, Tensor Network, Lattice Gauge theory
Hyun-Soo Kim UC Davis PhD, Physics (2019-present); joint w/ Complexity Sciences Center Quantum Cellular Automata, Quantum Dynamical Systems, Information in Complex Systems

Resources

Current Projects

Policies

  1. Hyperlink to an overleaf page if and only if it is an internal project.
  2. Project description should be no more than two lines.
People Collaborators Project Category Status
Michael, Bruno Dimerization in a class of O(n)-invariant quantum spin chains Nearly done
Arkin, Isaac Circuit depth vs. long range entanglement at finite energy density NISQ Nearly done
Evan, Isaac Efficient estimation of noise susceptibility of arbitrary quantum circuits NISQ
Zijian, Isaac Solvable model of many-body qubit recycling NISQ
Guangqi, Isaac Robust test of topologically ordered time crystal NISQ
Jintae, Isaac 3D Cluster State Construction Using Multiple Phonon Emitters QEC
Ian, Isaac Modular flow with quantum singular value transform
Isaac Guillaume Dauphinais (Xanadu) Fault-tolerant preparation of magic states with GKP codes QEC Hiatus
Isaac Daniel Ranard (MIT) Efficient certification of short-range entanglement NISQ/EB
Isaac Dmitry Abanin (U. of Geneva) Theory of influence matrix Hiatus
Isaac Zhaoyi Li (Stanford), Patrick Hayden (Stanford) Noise conversion technique via code concatenation QEC
Isaac Bowen Shi (UCSD) Li Gao (U. Houston) Continuity of modular commutator EB Hiatus
Zijian Guanyu Zhu (IBM) Exotic boundaries and domain walls of 3D color code

Completed Projects

People Collaborators Project Category Status
Isaac Sergey Bravyi (IBM), Robert Koenig (TUM), Alexander Kliesch (TUM) Adaptive constant-depth circuits for manipulating non-abelian anyons NISQ Done
Ian, Isaac Bowen Shi (UCSD), Yijian Zou (Stanford), Jonathan Sorce (Stanford) Modular commutator in conformal field theory EB preprint on arXiv, published in PRL

Group Presentations

Presentations by group members take place on the first meeting of every month. These presentations provide a more in-depth exploration and discussion of an individual group member's research. Food is provided for in-person attendees (courtesy of Isaac's startup funding)!

Date Presenter Title
6/1/2022 Arkin Circuit depth vs. Energy
7/6/2022 Evan Averaged circuit eigenvalue sampling (ACES)
8/3/2022 Guangqi Topologically Ordered Time Crystal in Toric code
9/7/2022 Ian From Modular Hamiltonians to Holographic Probes
10/5/2022 Isaac Switching between Z_{2k} Surface Codes
11/2/2022 Sanchayan An Introduction to Homological Codes
2/1/2023 Zijian Qubit recycling and the path counting problem
5/17/2023 Hyun-Soo A Discussion of Quantum Cellular Automata
6/28/2023 Ian A Quantum Algorithm for Modular Flow
9/6/2023 Zijian TBD
10/10/2023 Isaac Learning shallow quantum circuits
12/6/2023 Jintae UV/IR Mixing in Topological Phases

Upcoming presentations

Past presentations

  • February 1, 2023: Zijian Song. Qubit recycling and the path counting problem.
    Abstract: Recently, it was shown that the qudits used in circuits of a convolutional form can be reset unitarily, even without measurement. In the work arXiv: 2301.03725, we analyze the fidelity of this protocol for a family of quantum circuits and establish a connection between this problem and the path counting problem.
    In this talk I’ll first introduce the random quantum circuit and the qubit recycling protocol. Then I’ll show how the calculation is connected to the path counting problem in the noiseless case. Finally I’ll discuss the general noisy cases and compare our resuI might try lt with the previous numerical work.
  • November 2, 2022: Sanchayan Dutta. An Introduction to Homological Codes with an Empahsis on Fourier and Poincaré Dualities. Video recording and slides.
  • October 5, 2022: Isaac Kim. Switching between Z_{2k} Surface Codes.
  • September 14, 2022: Ian Lim. From Modular Hamiltonians to Holographic Probes. Abstract: For a subsystem of a quantum state, the modular Hamiltonian is an operator closely linked to the entanglement of that subsystem with the whole state. I will review some recent work (arXiv:2206.00027) around a related entanglement measure called the modular commutator in the context of conformal field theory (CFT). I will also present some ongoing work around a "modular flow" associated to the modular Hamiltonian, and its holographic interpretation.
  • August 4, 2022: Guangqi Zhao. Topologically Ordered Time Crystal in Toric code. Video recording and slides.
  • July 6, 2022: Evan Hockings. Implementing averaged circuit eigenvalue sampling on the surface code. Video recording and slides.
    Abstract: Averaged circuitI might try eigenvalue sampling (ACES) is a recently introduced technique for scalably characterising the noise associated with Clifford circuits. One particularly promising application is the circuits that implement error-correcting codes such as the surface code, as detailed noise characterisation may be leveraged to improve decoders. ACES is able to characterise the noise associated with an arbitrarily large surface code in a constant number of experiments.
  • June 1, 2022: Arkin Tikku (circuit depth lower bound project).
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Extremal Density Matrices

:::danger Last update: 8/30/2021, Isaac Kim Unfortunately, this line of approach seems to be too restrictive; see the last section for the underlying reason. Therefore, the notion of extremality, at least the one defined in this document, does not seem like a promising approach. Nevertheless, this document is left as is because there are some interesting concepts introduced here. Some of those concepts may be migrated to a separate note in the future. ::: Consider a quantum spin system arranged on $\mathbb{R}^2$. We can partition $\mathbb{R}^2$ into a set of $2$-cells, $1$-cells, and $0$-cells. Each $2$-cell and $1$-cell is homeomorphic to a disk and an open interval, respectively. The $0$-cells are points. In the figure below, a $2$-cell is represented by a red cell, a $1$-cell is represented by a blue line, and a $0$-cell is represented by a green dot.

Aug 30, 2021
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