An initialization strategy for addressing barren plateaus in parametrized quantum circuits
Parametrized quantum circuits initialized with random initial parameter values are characterized by barren plateaus where the gradient becomes exponentially small in the number of qubits. In this technical note we theoretically motivate and empirically validate an initialization strategy which can r...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
2019-12-01
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| Series: | Quantum |
| Online Access: | https://quantum-journal.org/papers/q-2019-12-09-214/pdf/ |
| _version_ | 1828487524093263872 |
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| author | Edward Grant Leonard Wossnig Mateusz Ostaszewski Marcello Benedetti |
| author_facet | Edward Grant Leonard Wossnig Mateusz Ostaszewski Marcello Benedetti |
| author_sort | Edward Grant |
| collection | DOAJ |
| description | Parametrized quantum circuits initialized with random initial parameter values are characterized by barren plateaus where the gradient becomes exponentially small in the number of qubits. In this technical note we theoretically motivate and empirically validate an initialization strategy which can resolve the barren plateau problem for practical applications. The technique involves randomly selecting some of the initial parameter values, then choosing the remaining values so that the circuit is a sequence of shallow blocks that each evaluates to the identity. This initialization limits the effective depth of the circuits used to calculate the first parameter update so that they cannot be stuck in a barren plateau at the start of training. In turn, this makes some of the most compact ansätze usable in practice, which was not possible before even for rather basic problems. We show empirically that variational quantum eigensolvers and quantum neural networks initialized using this strategy can be trained using a gradient based method. |
| first_indexed | 2024-12-11T09:52:14Z |
| format | Article |
| id | doaj.art-33547db1b3dc48cabb1cc1d73081ac57 |
| institution | Directory Open Access Journal |
| issn | 2521-327X |
| language | English |
| last_indexed | 2024-12-11T09:52:14Z |
| publishDate | 2019-12-01 |
| publisher | Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften |
| record_format | Article |
| series | Quantum |
| spelling | doaj.art-33547db1b3dc48cabb1cc1d73081ac572022-12-22T01:12:22ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2019-12-01321410.22331/q-2019-12-09-21410.22331/q-2019-12-09-214An initialization strategy for addressing barren plateaus in parametrized quantum circuitsEdward GrantLeonard WossnigMateusz OstaszewskiMarcello BenedettiParametrized quantum circuits initialized with random initial parameter values are characterized by barren plateaus where the gradient becomes exponentially small in the number of qubits. In this technical note we theoretically motivate and empirically validate an initialization strategy which can resolve the barren plateau problem for practical applications. The technique involves randomly selecting some of the initial parameter values, then choosing the remaining values so that the circuit is a sequence of shallow blocks that each evaluates to the identity. This initialization limits the effective depth of the circuits used to calculate the first parameter update so that they cannot be stuck in a barren plateau at the start of training. In turn, this makes some of the most compact ansätze usable in practice, which was not possible before even for rather basic problems. We show empirically that variational quantum eigensolvers and quantum neural networks initialized using this strategy can be trained using a gradient based method.https://quantum-journal.org/papers/q-2019-12-09-214/pdf/ |
| spellingShingle | Edward Grant Leonard Wossnig Mateusz Ostaszewski Marcello Benedetti An initialization strategy for addressing barren plateaus in parametrized quantum circuits Quantum |
| title | An initialization strategy for addressing barren plateaus in parametrized quantum circuits |
| title_full | An initialization strategy for addressing barren plateaus in parametrized quantum circuits |
| title_fullStr | An initialization strategy for addressing barren plateaus in parametrized quantum circuits |
| title_full_unstemmed | An initialization strategy for addressing barren plateaus in parametrized quantum circuits |
| title_short | An initialization strategy for addressing barren plateaus in parametrized quantum circuits |
| title_sort | initialization strategy for addressing barren plateaus in parametrized quantum circuits |
| url | https://quantum-journal.org/papers/q-2019-12-09-214/pdf/ |
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