Superefficient long-lived multiresonator quantum memory

Abstract

In this paper, we propose a scheme of a long-lived broadband superefficient multiresonator quantum memory in which a common resonator is connected with an external waveguide and with a system of high-quality miniresonators containing long-lived resonant electron spin ensembles. The scheme with 4 miniresonators has been analyzed in details and it was shown that it is possible to store an input broadband signal field to the electron spin ensembles with quantum efficiency 99.99%. The considered multiresonator system opens the way to elaboration of efficient multiqubit quantum memory devices for superconducting quantum computer.

Superefficient cascade multiresonator quantum memory

“…Moreover high quality of the resonators makes it possible to considerable enhance the constant coupling with light signals and resonant atomic ensembles herewith the broadband system of resonators allows reducing the effects of relaxation and decoherence due to the transition to faster storage processes. These properties promise getting higher QM efficiency and using these systems in circuits of the universal quantum computers [2,[25][26][27].…”

Spectrally Improved Controllable Frequency Comb Quantum Memory

“…Such schemes demonstrate the possibility of a significant increase in the operating spectral range of the QM and high quality of the resonators makes it possible to considerable enhance the constant coupling both between neighboring high-Q resonators and light-atoms interaction in the resonators. The latter properties make this type of QM promising for use in circuits of a universal quantum computer [19][20][21][22][23][24].…”

“…The ideal infinite-broadband QM is characterized by the condition T rel (ν) = T (ν)/T (0) = 1 for any frequency detuning ν, which can not be achieved due to the finiteness of the number of absorbers. For a system with a finite number of absorbers, the last condition must be replaced by an approximate equality T (ν) ∼ = T (0), which is equivalent to optimizing the quantity |T (ν) − T (0)| 2 in a wide frequency range [22,23]. Physically, this means that the function T (ν) has a spectral plateau in some neighborhood ν = 0 (the region where the function has a sufficiently small changes), which can be made more flat and wide due to the optimization and that increases the effective QM bandwidth, respectively.…”

“…Physically, this means that the function T (ν) has a spectral plateau in some neighborhood ν = 0 (the region where the function has a sufficiently small changes), which can be made more flat and wide due to the optimization and that increases the effective QM bandwidth, respectively. According to [22], for QM with N 0 resonators coupling the waveguide, we use the objective function H = N0/2 m=−N0/2 |T (ν = 2m/N 0 )| 2 for optimization (minimization) in spectral range of the order N 0 ∆ (∆ = 1).…”

“…For the blocks gluing, the maximum deviation of |T rel (ν) − 1|occurs at the midpoint of the spectrum between the spectra of neighboring blocks Therefore, the choice of the optimal spectral distance δ for gluing the 2 fully optimized QM blocks was carried out proceeding from the simple rule T (ν = −δ) = T (ν = 0) = T (ν = δ), which reliably guarantees the homogeneity of the entire finite region. The choice of the optimal coupling constant k for the case of equidistant frequency comb was carried out on the basis of optimization of the quantity |T (ν) − T (0)| 2 according to [22], which reduces to solving the equation ∂ 2 ν T (ν)| ν=0 = 0 with respect to k. As a result, we obtained the detuning δ = 2, 18 for gluing the optimal QM blocks and k = 4, 26 for the case of 4 resonators. As it can be seen in Fig.…”