dorsal/arxiv
View SchemaHow to project qubits faster using quantum feedback
| Authors | Kurt Jacobs |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0301056 |
| URL | https://arxiv.org/abs/quant-ph/0301056 |
| DOI | 10.1103/PhysRevA.67.030301 |
| Journal | Phys. Rev. A 67, 030301(R) (2003) |
Abstract
When one performs a continuous measurement, whether on a classical or quantum system, the measurement provides a certain average rate at which one becomes certain about the state of the system. For a quantum system this is an average rate at which the system is projected onto a pure state. We show that for a standard kind of continuous measurement, for a qubit this rate may be increased by applying unitary operations during the measurement (that is, by using Hamiltonian feedback), in contrast to the equivalent measurement on a classical bit, where reversible operations cannot be used to enhance the rate of entropy reduction. We determine the optimal feedback algorithm and discuss the Hamiltonian resources required.
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"abstract": "When one performs a continuous measurement, whether on a classical or quantum\nsystem, the measurement provides a certain average rate at which one becomes\ncertain about the state of the system. For a quantum system this is an average\nrate at which the system is projected onto a pure state. We show that for a\nstandard kind of continuous measurement, for a qubit this rate may be increased\nby applying unitary operations during the measurement (that is, by using\nHamiltonian feedback), in contrast to the equivalent measurement on a classical\nbit, where reversible operations cannot be used to enhance the rate of entropy\nreduction. We determine the optimal feedback algorithm and discuss the\nHamiltonian resources required.",
"arxiv_id": "quant-ph/0301056",
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"doi": "10.1103/PhysRevA.67.030301",
"journal_ref": "Phys. Rev. A 67, 030301(R) (2003)",
"title": "How to project qubits faster using quantum feedback",
"url": "https://arxiv.org/abs/quant-ph/0301056"
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