Verfahren zur Messung von Selbstker in einem Physikalischen Quantensystem mit Konfiguration zum Hosten eines Bosonischen Code-Qubit

Details

Veröffentlichungs-Nr.

EP4764968

Anmeldetag

20. Dezember 2024

Veröffentlichung

24. Juni 2026

Rechtsraum

EP

IPC

G06N10/20, G06N10/70

Abstract

A method of measuring self-Kerr in a physical quantum system configured to host a bosonic code qubit, comprises the following operations:1) providing a physical quantum system configured to host a bosonic code qubit, said physical quantum system comprising (i) a quantum circuit comprising oscillators hosting a buffer or readout mode and a memory mode, and a non-linear element coupling the buffer or readout mode to the memory mode, and (ii) a control circuit configured to apply one or more control signals to the quantum circuit to stabilize the bosonic code qubit in the memory mode and further configured to receive measurement signals from at least the buffer or readout mode,2) define a coherent state (α) for the memory mode, and, for each of a plurality of coherent state amplitudes and each of a plurality of durations (t),a. prepare, using the control circuit, said coherent state (α) in the memory having one of said plurality of coherent state amplitudes,b. wait for a period of time having one of said duration (t),c. apply, using the control circuit, one or more control signals to said quantum circuit such that the quantum circuit is in a resonant regime |i * ω_a - ω_b| = j * |ω_CS| if said one or more control signals comprise an AC component having an angular frequency ω_CS or |i * ω_a - ω_b| = 0 if said one or more control signals comprise only DC components, resulting in an interaction, mediated via said non-linear element, in said physical quantum system which results in a Hamiltonian having a leading term of the general formula H_i,(j,0) ∝ ξ_(j,0)(a^†)ⁱb + h.c. ... , where is the annihilation operator of said memory mode, i is an integer superior or equal to 1, ω_a is the angular frequency of the memory mode whilst the quantum circuit is in the resonant regime, j is an integer superior or equal to 1, b is the annihilation operator of the buffer or readout mode, ω_b is the angular frequency of the buffer or readout mode whilst the quantum circuit is in the resonant regime, and ξ_(j,0) is the strength of said interaction, andd. simultaneously to operation 2)c., using the control circuit, receiving measurement signals comprising at least the mode phase and/or mode amplitude of the buffer or readout mode,3) derive an effective detuning or a decayed mode amplitude for each coherent state amplitude, by fitting of the measurements of operation 2)d. which are associated with said each coherent state amplitude,4) derive at least one of self-Kerr coefficients, stark-shift detuning, and memory dephasing rate from the plurality of effective detunings or decayed mode amplitudes of operation 3) by fitting of a function of the absolute magnitude squares of coherent state amplitude in said memory mode.

Anmelder

Firma

Alice & Bob

Land

🇫🇷 Frankreich

Fachgebiete