dorsal/arxiv
View SchemaStrictly contractive quantum channels and physically realizable quantum computers
| Authors | Maxim Raginsky |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0105141 |
| URL | https://arxiv.org/abs/quant-ph/0105141 |
| DOI | 10.1103/PhysRevA.65.032306 |
| Journal | Phys. Rev. A 65, 032306 (2002) |
Abstract
We study the robustness of quantum computers under the influence of errors modelled by strictly contractive channels. A channel $T$ is defined to be strictly contractive if, for any pair of density operators $\rho,\sigma$ in its domain, $\| T\rho - T\sigma \|_1 \le k \| \rho-\sigma \|_1$ for some $0 \le k < 1$ (here $\| \cdot \|_1$ denotes the trace norm). In other words, strictly contractive channels render the states of the computer less distinguishable in the sense of quantum detection theory. Starting from the premise that all experimental procedures can be carried out with finite precision, we argue that there exists a physically meaningful connection between strictly contractive channels and errors in physically realizable quantum computers. We show that, in the absence of error correction, sensitivity of quantum memories and computers to strictly contractive errors grows exponentially with storage time and computation time respectively, and depends only on the constant $k$ and the measurement precision. We prove that strict contractivity rules out the possibility of perfect error correction, and give an argument that approximate error correction, which covers previous work on fault-tolerant quantum computation as a special case, is possible.
{
"annotation_id": "b7e96816-fb7a-434a-9117-588a57360b90",
"date_created": "2026-03-02T18:01:45.511000Z",
"date_modified": "2026-03-02T18:01:45.511000Z",
"file_hash": "a82cf86cf4bce99af78c24ed5525c111d2e37251c2c882a809754240a63f5993",
"private": false,
"record": {
"abstract": "We study the robustness of quantum computers under the influence of errors\nmodelled by strictly contractive channels. A channel $T$ is defined to be\nstrictly contractive if, for any pair of density operators $\\rho,\\sigma$ in its\ndomain, $\\| T\\rho - T\\sigma \\|_1 \\le k \\| \\rho-\\sigma \\|_1$ for some $0 \\le k \u003c\n1$ (here $\\| \\cdot \\|_1$ denotes the trace norm). In other words, strictly\ncontractive channels render the states of the computer less distinguishable in\nthe sense of quantum detection theory. Starting from the premise that all\nexperimental procedures can be carried out with finite precision, we argue that\nthere exists a physically meaningful connection between strictly contractive\nchannels and errors in physically realizable quantum computers. We show that,\nin the absence of error correction, sensitivity of quantum memories and\ncomputers to strictly contractive errors grows exponentially with storage time\nand computation time respectively, and depends only on the constant $k$ and the\nmeasurement precision. We prove that strict contractivity rules out the\npossibility of perfect error correction, and give an argument that approximate\nerror correction, which covers previous work on fault-tolerant quantum\ncomputation as a special case, is possible.",
"arxiv_id": "quant-ph/0105141",
"authors": [
"Maxim Raginsky"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.65.032306",
"journal_ref": "Phys. Rev. A 65, 032306 (2002)",
"title": "Strictly contractive quantum channels and physically realizable quantum computers",
"url": "https://arxiv.org/abs/quant-ph/0105141"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "0fed7bea-d138-4dca-a070-4376d1982560",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}