Microwave multimode memory with an erbium spin ensemble

Abstract

Hybrid quantum system combining circuit QED with spin doped solids are an attractive platform for distributed quantum information processing. There, the magnetic ions serve as coherent memory elements and reversible conversion elements of microwave to optical qubits. Among many possible spin-doped solids, erbium ions offer the unique opportunity of a coherent conversion of microwave photons into the telecom C-band at 1.54 µm employed for long distance communication. In our work, we perform a time-resolved electron spin resonance study of an Er 3+ :Y2SiO5 spin ensemble at milli-Kelvin temperatures and demonstrate multimode storage and retrieval of up to 16 coherent microwave pulses. The memory efficiency is measured to be 10 −4 at the coherence time of T2 = 5.6 µs. We observe a saturation of the spin coherence time below 50mK due to full polarization of the surrounding electronic spin bath.A future quantum communication technology will combine three basic types of subsystems: Transmission channels, repeater stations and information processing nodes [1,2]. Similarly to classical communication networks, photons propagating through optical fiber channels are ideal for carrying quantum states over long distances and distribute entanglement between information processing nodes [3]. These computational nodes or quantum processors may be realized by employing single atomic or macroscopic solid-state systems. Among a plethora of solid state devices, superconducting (SC) qubits are one of the most promising building blocks for a future quantum computer [4]. Many ground breaking experiments have recently been demonstrated with SC qubits including the measurement of long coherence and relaxation times of up to 0.1 ms [5], coherent operation of up to three-qubit processors [6], the implementation of a deterministic two-qubit gate [7] and the realization of a basic surface code for fault tolerant computing [8]. These qubits operate at microwave frequencies and cryogenic temperatures. In order to embed them into the emerging quantum optical internet technology a coherent interface between optical and microwave photons is required [9].Ensembles of rare-earth (RE) ions doped into a crystal are a suitable system for coherent photon conversion between optical and microwave frequency bands [10][11][12]. Such RE doped crystals are currently at the forefront of quantum communication research, where many thrilling achievements such as the demonstration of a quantum memory at the optical telecom C-band [13], high efficiency storage of optical photons [14], generation of entanglement between two RE doped crystals [15] and quantum teleportation between a telecom O-band photon (1.34 µm) and a RE doped crystal [16] have been reported. Also, RE doped crystals are considered to have a great potential as a multimode optical memory element in a future quantum repeater technology [17], and storage and retrieval of 64 temporal optical modes at the single photon level has been demonstrated [18].A crucial step towards the development of a microwav...

High-resolution optical spectroscopy and magnetic properties ofYb3+inY2SiO5Welinski1, Ferrier2, Afzelius3 et al. 2016Phys. Rev. B404391View full textAdd to dashboardCite

“…This can be used to interface microwave photons to a RE doped crystal through a superconducting resonator 22,23 and obtain quantum memories for superconducting qubits. [24][25][26] In this case too, nuclear hyperfine transitions can provide long storage time. We recently showed that 145 Nd 3+ :Y 2 SiO 5 hyperfine transitions have ground state coherence lifetimes up to 9 ms at 5 K, whereas the electron spin T 2 is about 100 µs.…”

Coherent Storage of Microwave Excitations in Rare-Earth Nuclear Spins

“…Such memo ries offer the possibility exploiting electron spin coherence times of up to seconds [3] as a resource for superconducting qubits, whose coherence times so far extend only to tens of microseconds [4], Strong coupling has been observed between superconducting resonators and various paramag netic impurities, including NV centers in diamond [5] and erbium ions in Y2S i0 5 (YSO) and YA103 [6][7][8], leading to reversible coherent storage of (large numbers of) microwave photons within spin ensembles [9,10]. These para magnetic impurities are often coupled to nuclear spins that can offer a further resource for storage-electronic spin coherences can be transferred to and from a nuclear spin [11][12][13], to access coherence times as long as hours [14],…”

Analysis and calibration techniques for superconducting resonators

“…(3) is evaluated in this limit the expressions reduce to the first-order lumped-circuit treatments described in the literature for a single resonator in transmission. 11,12,38 However, we find that to faithfully reproduce the interactions between resonators over a wide spectral bandwidth the full functional form presented here is required.…”