2009/04/30 by Fernando Pastawski, Alastair Kay, Norbert Schuch +2 · 23 citations
Computer Science · Mathematics · Physics and Astronomy · #Computer science #Depolarization #Hamiltonian (control theory) #Mathematics #Noise (video) #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum mechanics #Qubit #Statistical physics #quant-ph
paper · pdf · doi:10.1103/physrevlett.103.080501
published in Physical Review Letters 103(8), 080501 (American Physical Society) · 4 pages, 2 figures. Accepted version, Journal-Ref added
openalex publication_date 2009/08/20 · arxiv created 2009/09/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the possibilities and limitations of passive Hamiltonian protection of a quantum memory against depolarizing noise. Without protection, the lifetime of a single qubit is independent of N, the number of qubits composing the memory. In the presence of a protecting Hamiltonian, the lifetime increases at most logarithmically with N. We construct an explicit time-independent Hamiltonian which saturates this bound, exploiting the noise itself to achieve the protection.