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Search Publications by: Michael Gullans (Fed)

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Displaying 1 - 25 of 29

Clifford-Deformed Surface Codes

March 19, 2024
Arpit Dua, Aleksander Kubica, Liang Jiang, Steven Flammia, Michael Gullans
Kitaev's toric/surface code and its numerous variants provide promising approaches to practi- cal quantum error correction (QEC). As recently discovered, a careful choice of the code variant and lattice layout can dramatically reduce logical error rate for

Precision Bounds on Continuous-Variable State Tomography Using Classical Shadows

March 18, 2024
Srilekha Gandhari, Victor Albert, Thomas Gerrits, Jacob Taylor, Michael Gullans
Shadow tomography is a framework for constructing succinct descriptions of quantum states, called classical shadows, with powerful methods to bound the estimators used. Classical shadows are well-studied in the discrete-variable case, which consists of sta

Logical quantum processor based on reconfigurable atom arrays

December 6, 2023
Dolev Bluvstein, Simon Evered, Alexandra Geim, Sophie Li, Hengyun Zhou, Tom Manovitz, Sepehr Ebadi, Madelyn Cain, Marcin Kalinowski, Dominik Hangleiter, J. Pablo Bonilla Ataides, Nishad Maskara, Iris Cong, Xun Gao, Pedro Rodriguez, Thomas Karolyshyn, Giulia Semeghini, Michael Gullans, Markus Greiner, Vladan Vuletic, Mikahil Lukin
Suppressing errors is the central challenge for useful quantum computing and quantum error correction is believed to be the key to large-scale quantum processing. Here we report the realization of a programmable quantum processor based on encoded logical

Quantum Lego Expansion Pack: Enumerators from Tensor Networks

August 9, 2023
ChunJun Cao, Michael Gullans, Brad Lackey, Zitao Wang
We provide the first tensor network method for computing quantum weight enumerator polynomials in the most general form. As a corollary, if a quantum code has a known tensor network construction of its encoding map, our method produces an algorithm that

Crystalline Quantum Circuits

July 31, 2023
Grace Sommers, David Huse, Michael Gullans
Random quantum circuits continue to inspire a wide range of applications in quantum information science, while remaining analytically tractable through probabilistic methods. Motivated by the need for deterministic circuits with similar applications, we

Compressed gate characterization for quantum devices with time-correlated noise

July 22, 2023
Michael Gullans, Miguel Caranti, Adam Mills, Jason Petta
As quantum devices make steady progress towards intermediate scale and fault-tolerant quantum computing, it is essential to develop rigorous and efficient measurement protocols that account for known sources of noise in each architecture. Most existing

Infinite-randomness criticality in monitored quantum dynamics with static disorder

June 23, 2023
Aidan Zabalo, Justin Wilson, Michael Gullans, Romain Vasseur, Sarang Goplakrishnan, David Huse, Jed Pixley
We consider a model of monitored quantum dynamics with quenched spatial randomness: specifically, random quantum circuits with spatially varying measurement rates. These circuits undergo a measurement-induced phase transition (MIPT) in their entanglement

Neural-network decoders for measurement induced phase transitions

May 22, 2023
Hossein Dehghani, Ali Lavasani, Mohammad Hafezi, Michael Gullans
Open quantum systems have been shown to host a plethora of exotic dynamical phases. Measurement-induced entanglement phase transitions in monitored quantum systems are a striking example of this phenomena. However, naive realizations of such phase

Self-dual quasiperiodic percolation

February 27, 2023
Grace Sommers, Michael Gullans, David Huse
How does the percolation transition behave in the absence of quenched randomness? To address this question, we study a nonrandom self-dual quasiperiodic model of square-lattice bond percolation. Through a numerical study of cluster sizes and wrapping

Tight Bounds on the Convergence of Noisy Random Circuits to the Uniform Distribution

December 16, 2022
Michael Gullans, Abhinav Deshpande, Bill Fefferman, Alexey Gorshkov, Pradeep Niroula, Oles Shtanko
We study the properties of output distributions of noisy, random circuits. We obtain upper and lower bounds on the expected distance of the output distribution from the uniform distribution. These bounds are tight with respect to the dependence on circuit

High-Fidelity State Preparation, Quantum Control, and Readout of an Isotopically Enriched Silicon Spin Qubit

December 12, 2022
Adam Mills, Charlie Guinn, Michael Gullans, Mayer Feldman, Anthony Sigillito, M. Rakher, J. Kerckhoff, A. C. Jackson, Jason Petta
Quantum systems must be prepared, controlled, and measured with high fidelity in order to per- form complex quantum algorithms. Control fidelities have greatly improved in silicon spin qubits, but state preparation and readout fidelities have generally

Constructing quantum many-body scar Hamiltonians from Floquet automata

November 22, 2022
Michael Gullans, Pierre-Gabriel Rozon, Kartiek Agarwal
We provide a systematic approach for constructing approximate quantum many-body scars (QMBS) starting from two-layer Floquet automaton circuits that exhibit trivial many-body re- vivals. We do so by applying successively more restrictions that force local

Measurement-induced quantum phases realized in a trapped-ion quantum computer

June 2, 2022
Michael Gullans, Alexey Gorshkov, David Huse, Christopher Monroe, Crystal Noel, Pradeep Niroula, Daiwei Zhu, Andrew Risinger, Laird Egan, Debopriyo Biswas, Marko Cetina
Many-body open quantum systems balance internal dynamics against decoherence from interactions with an environment. Here, we explore this balance via random quantum circuits implemented on a trapped-ion quantum computer, where the system evolution is

Two-qubit silicon quantum processor with operation fidelity exceeding 99%

April 6, 2022
Michael Gullans, Adam Mills, Charlie Guinn, Anthony Sigillito, Mayer Feldman, Nielsen Erik, Jason Petta
Silicon spin qubits satisfy the necessary criteria for quantum information processing. However, precision is required to support error correction, namely high accuracy state preparation and readout as well as high fidelity single- and two-qubit control. We

Operator scaling dimensions and multifractality at measurement-induced transitions

February 3, 2022
Michael Gullans, Zabalo Aidan, Justin Wilson, Romain Vasseur, Andreas Ludwig, Sarang Gopalakrishnan Gopalakrishnan, David Huse, Jed Pixley
Repeated local measurements of quantum many body systems can induce a phase transition in their entanglement structure. These measurement-induced phase transitions (MIPTs) have been studied for various types of dynamics, yet most cases yield quantitatively

Quantum coding with low-depth random circuits

September 24, 2021
Michael Gullans, David A. Huse, Stefan Krastanov, Liang Jiang, Steven T. Flammia
Random quantum circuits have played a central role in establishing the computational advantages of near-term quantum computers over their conventional counterparts. Here, we use ensembles of low-depth random circuits with local connectivity in D ≥ 1

Observation of chiral photocurrent transport in the quantum Hall regime in graphene

May 24, 2021
Glenn S. Solomon, Olivier Gazzano, Bin Cao, Jiuning Hu, David B. Newell, Tobias Huber, Michael Gullans, Mohammad Hafezi, Tobias Grass
Optical excitation provides a powerful tool to investigate non-equilibrium physics in quantum Hall systems. Moreover, the length scale associated with photo-excited charge carries lies between that of local probes and global transport measurements. Here

Tunable three-body loss in a nonlinear Rydberg medium

May 5, 2021
James(Trey) Porto, Alexey Gorshkov, Michael Gullans, D. Ornelas-Huerta, Przemyslaw Bienias, A. Craddock, A. Hachtel, Marcin Kalinowski, Mary Lyon, Steven L. Rolston
Long-range Rydberg interactions, in combination with electromagnetically induced transparency(EIT), give rise to strongly interacting photons where the strength, sign, and form of the interactions are widely tunable and controllable. Such control can be

Entanglement and purification transitions in non-Hermitian quantum mechanics

April 30, 2021
Michael Gullans, Sarang Gopalakrishnan
A quantum system subject to continuous measurement and post-selection evolves according to a non- Hermitian Hamiltonian. We show that, as one increases the rate of post-selection, this non- Hermitian Hamiltonian can undergo a spectral phase transition. On

Photon thermalization via laser cooling of atoms

July 19, 2018
Chiao-Hsuan Wang, Michael Gullans, James V. Porto, William D. Phillips, Jacob Taylor
The cooling of atomic motion by scattered light enables a wide variety of technological and scientific explorations. Here we focus on laser cooling from the perspective of the light — specifi- cally, the scattering of light between different optical modes

Light-induced fractional quantum hall phases in graphene

December 15, 2017
Michael Gullans, Areg Ghazaryan, Pouyan Ghaemi, Mohammad Hafezi
We show how to realize two-component fractional quantum Hall phases in monolayer graphene by optically driving the system. A laser is tuned into resonance between two Landau levels of graphene and acts as a e ective tunneling term between these states. We