Trent Huang - Academia.edu (original) (raw)
Papers by Trent Huang
arXiv (Cornell University), May 27, 2024
Zenodo (CERN European Organization for Nuclear Research), Aug 16, 2023
Nature
Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable ... more Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the ‘arrow of time’ that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space–time3–10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11–13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15–17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,...
Bulletin of the American Physical Society, Mar 14, 2017
Microelectronic Engineering, Jun 1, 2003
Physical review research, Feb 22, 2022
arXiv (Cornell University), Jun 15, 2023
arXiv (Cornell University), Nov 9, 2022
An important measure of the development of quantum computing platforms has been the simulation of... more An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems [1–3]. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth [4–11]. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a fully correlated model [12–17], and an opportunity to validate recently introduced “purification-based” error-mitigation strategies [8–10]. We compare the performance of error mitigation based on doubling quantum resources in time (echo verification [10]) or in space (virtual distillation [8, 9]), on up to 20 qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques (e.g. post-selection); the gain from error mitigation is seen to increase with the system size. Employing these error mit...
arXiv (Cornell University), Sep 16, 2022
arXiv (Cornell University), Jun 10, 2022
Science, 2021
Quantum scrambling Information spreading in interacting quantum systems is of relevance to a wide... more Quantum scrambling Information spreading in interacting quantum systems is of relevance to a wide range of settings, from black holes to strange metals. Mi et al . used the Sycamore quantum processor to study this process. Through judicial design of quantum circuits, the researchers were able to separate the contributions of operator spreading and operator entanglement. Measuring the mean value and fluctuations of a specific correlator enabled quantifying these distinct contributions. —JS
Physical review letters, Jan 31, 2018
Superconducting qubits are an attractive platform for quantum computing since they have demonstra... more Superconducting qubits are an attractive platform for quantum computing since they have demonstrated high-fidelity quantum gates and extensibility to modest system sizes. Nonetheless, an outstanding challenge is stabilizing their energy-relaxation times, which can fluctuate unpredictably in frequency and time. Here, we use qubits as spectral and temporal probes of individual two-level-system defects to provide direct evidence that they are responsible for the largest fluctuations. This research lays the foundation for stabilizing qubit performance through calibration, design, and fabrication.
Superconductor Science and Technology, 2018
Nature, 2021
Quantum many-body systems display rich phase structure in their low-temperature equilibrium state... more Quantum many-body systems display rich phase structure in their low-temperature equilibrium states1. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases2–8that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC)7,9–15. Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order7,16,17. In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of...
Nature Physics
The leakage of quantum information out of the two computational states of a qubit into other ener... more The leakage of quantum information out of the two computational states of a qubit into other energy states represents a major challenge for quantum error correction. During the operation of an error-corrected algorithm, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of the logical error with scale, thus challenging the feasibility of quantum error correction as a path towards fault-tolerant quantum computation. Here, we demonstrate a distance-3 surface code and distance-21 bit-flip code on a quantum processor for which leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a tenfold reduction in the steady-state leakage population of the data qubits encoding the logical state and an average leakage population of less than 1 × 10−3 throughout the entire device. Our leakage removal p...
arXiv (Cornell University), May 27, 2024
Zenodo (CERN European Organization for Nuclear Research), Aug 16, 2023
Nature
Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable ... more Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the ‘arrow of time’ that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space–time3–10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11–13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15–17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,...
Bulletin of the American Physical Society, Mar 14, 2017
Microelectronic Engineering, Jun 1, 2003
Physical review research, Feb 22, 2022
arXiv (Cornell University), Jun 15, 2023
arXiv (Cornell University), Nov 9, 2022
An important measure of the development of quantum computing platforms has been the simulation of... more An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems [1–3]. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth [4–11]. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a fully correlated model [12–17], and an opportunity to validate recently introduced “purification-based” error-mitigation strategies [8–10]. We compare the performance of error mitigation based on doubling quantum resources in time (echo verification [10]) or in space (virtual distillation [8, 9]), on up to 20 qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques (e.g. post-selection); the gain from error mitigation is seen to increase with the system size. Employing these error mit...
arXiv (Cornell University), Sep 16, 2022
arXiv (Cornell University), Jun 10, 2022
Science, 2021
Quantum scrambling Information spreading in interacting quantum systems is of relevance to a wide... more Quantum scrambling Information spreading in interacting quantum systems is of relevance to a wide range of settings, from black holes to strange metals. Mi et al . used the Sycamore quantum processor to study this process. Through judicial design of quantum circuits, the researchers were able to separate the contributions of operator spreading and operator entanglement. Measuring the mean value and fluctuations of a specific correlator enabled quantifying these distinct contributions. —JS
Physical review letters, Jan 31, 2018
Superconducting qubits are an attractive platform for quantum computing since they have demonstra... more Superconducting qubits are an attractive platform for quantum computing since they have demonstrated high-fidelity quantum gates and extensibility to modest system sizes. Nonetheless, an outstanding challenge is stabilizing their energy-relaxation times, which can fluctuate unpredictably in frequency and time. Here, we use qubits as spectral and temporal probes of individual two-level-system defects to provide direct evidence that they are responsible for the largest fluctuations. This research lays the foundation for stabilizing qubit performance through calibration, design, and fabrication.
Superconductor Science and Technology, 2018
Nature, 2021
Quantum many-body systems display rich phase structure in their low-temperature equilibrium state... more Quantum many-body systems display rich phase structure in their low-temperature equilibrium states1. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases2–8that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC)7,9–15. Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order7,16,17. In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of...
Nature Physics
The leakage of quantum information out of the two computational states of a qubit into other ener... more The leakage of quantum information out of the two computational states of a qubit into other energy states represents a major challenge for quantum error correction. During the operation of an error-corrected algorithm, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of the logical error with scale, thus challenging the feasibility of quantum error correction as a path towards fault-tolerant quantum computation. Here, we demonstrate a distance-3 surface code and distance-21 bit-flip code on a quantum processor for which leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a tenfold reduction in the steady-state leakage population of the data qubits encoding the logical state and an average leakage population of less than 1 × 10−3 throughout the entire device. Our leakage removal p...