Automatic post-selection by ancillae thermalization
Tasks such as classification of data and determining the ground state of a Hamiltonian cannot be carried out through purely unitary quantum evolution. Instead, the inherent nonunitarity of the measurement process must be harnessed. Post-selection and its extensions provide a way to do this. However,...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2021-08-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.3.033151 |
| _version_ | 1797210919891107840 |
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| author | L. Wright F. Barratt J. Dborin G. H. Booth A. G. Green |
| author_facet | L. Wright F. Barratt J. Dborin G. H. Booth A. G. Green |
| author_sort | L. Wright |
| collection | DOAJ |
| description | Tasks such as classification of data and determining the ground state of a Hamiltonian cannot be carried out through purely unitary quantum evolution. Instead, the inherent nonunitarity of the measurement process must be harnessed. Post-selection and its extensions provide a way to do this. However, they make inefficient use of time resources—a typical computation might require O(2^{m}) measurements over m qubits to reach a desired accuracy and cannot be done intermittently on current (superconducting-based) NISQ devices. We propose a method inspired by thermalization that harnesses insensitivity to the details of the bath. We find a greater robustness to gate noise by coupling to this bath, with a similar cost in time and more qubits compared to alternate methods for inducing nonlinearity such as fixed-point quantum search for oblivious amplitude amplification. Post-selection on m ancillae qubits is replaced with tracing out O[logε/log(1−p)] (where p is the probability of a successful measurement) to attain the same accuracy as the post-selection circuit. We demonstrate this scheme on the quantum perceptron, quantum gearbox, and phase estimation algorithm. This method is particularly advantageous on current quantum computers involving superconducting circuits. |
| first_indexed | 2024-04-24T10:18:15Z |
| format | Article |
| id | doaj.art-430c325aa1bc42cc968dfd2142aa77e8 |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:18:15Z |
| publishDate | 2021-08-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-430c325aa1bc42cc968dfd2142aa77e82024-04-12T17:12:54ZengAmerican Physical SocietyPhysical Review Research2643-15642021-08-013303315110.1103/PhysRevResearch.3.033151Automatic post-selection by ancillae thermalizationL. WrightF. BarrattJ. DborinG. H. BoothA. G. GreenTasks such as classification of data and determining the ground state of a Hamiltonian cannot be carried out through purely unitary quantum evolution. Instead, the inherent nonunitarity of the measurement process must be harnessed. Post-selection and its extensions provide a way to do this. However, they make inefficient use of time resources—a typical computation might require O(2^{m}) measurements over m qubits to reach a desired accuracy and cannot be done intermittently on current (superconducting-based) NISQ devices. We propose a method inspired by thermalization that harnesses insensitivity to the details of the bath. We find a greater robustness to gate noise by coupling to this bath, with a similar cost in time and more qubits compared to alternate methods for inducing nonlinearity such as fixed-point quantum search for oblivious amplitude amplification. Post-selection on m ancillae qubits is replaced with tracing out O[logε/log(1−p)] (where p is the probability of a successful measurement) to attain the same accuracy as the post-selection circuit. We demonstrate this scheme on the quantum perceptron, quantum gearbox, and phase estimation algorithm. This method is particularly advantageous on current quantum computers involving superconducting circuits.http://doi.org/10.1103/PhysRevResearch.3.033151 |
| spellingShingle | L. Wright F. Barratt J. Dborin G. H. Booth A. G. Green Automatic post-selection by ancillae thermalization Physical Review Research |
| title | Automatic post-selection by ancillae thermalization |
| title_full | Automatic post-selection by ancillae thermalization |
| title_fullStr | Automatic post-selection by ancillae thermalization |
| title_full_unstemmed | Automatic post-selection by ancillae thermalization |
| title_short | Automatic post-selection by ancillae thermalization |
| title_sort | automatic post selection by ancillae thermalization |
| url | http://doi.org/10.1103/PhysRevResearch.3.033151 |
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