Measurement-based quantum computing with a spin ensemble coupled to a stripline cavity

Abstract

Abstract. Recently, a new form of quantum memory was proposed. The storage medium is an ensemble of electron spins, coupled to a stripline cavity and an ancillary readout system. Theoretical studies suggest that the system should be capable of storing numerous qubits within the ensemble, and an experimental proof-of-concept has already been performed. Here, we show that this minimal architecture is not limited to storage but is in fact capable of full quantum processing by employing measurement-based entanglement. The technique appears to be remarkably robust against the anticipated dominant error types. The key enabling component, namely a readout technology that nondestructively determines 'are there n photons in the cavity?', has already been realized experimentally.

Critical phenomena and nonlinear dynamics in a spin ensemble strongly coupled to a cavity. II. Semiclassical-to-quantum boundary

“…In particular, so-called hybrid quantum systems, whose technological relevance requires them to be open, have shifted to the center of attention over the last decade [2,3]. As a prominent example, spin ensembles coupled to a cavity mode emerged as a powerful platform for quantum computation [4][5][6], quantum memories [7][8][9], and quantum communication [10,11]. Beside their technological significance, the driven and dissipative character of spin-cavity systems makes them also wellsuited to study fundamental aspects of non-equilibrium many-body physics [12][13][14].…”

Quantum Computers as Universal Quantum Simulators: State‐of‐the‐Art and Perspectives

“…For instance, ensembles of non‐interacting spins in paramagnetic materials coherently coupled to superconducting microwave resonators have been proposed as the backbone of a novel hybrid quantum technology . This hybrid architecture would exploit the long coherence times of spin ensembles and the easy manipulation of photons in tunable resonators.…”

“…For instance, ensembles of non-interacting spins in paramagnetic materials coherently coupled to superconducting microwave resonators [216][217][218] have been proposed as the backbone of a novel hybrid quantum technology. [99,100,219] This hybrid architecture would exploit the long coherence times of spin ensembles and the easy manipulation of photons in tunable resonators. A full digital quantum computing architecture has been devised, [43,220] for which we report an example in Figure 13a, where the transverse field Ising model of three spins (see Hamiltonian model in the inset) is theoretically shown to be simulated with a large overall fidelity (≈95% on average) when realistic dissipation parameters are assumed.…”

Robustness of quantum gates with hybrid spin-photon qubits in superconducting resonators

“…For these reasons, hybrid devices are being investigated [10][11][12][13][14][15], in order to benefit from the fast manipulation rates of superconducting qubits, such as Cooper-pair boxes (CPBs) or transmons [1,4,6,7,16], while avoiding the limitations coming from their relaxation and dephasing mechanisms [8,9]. In such devices, superconducting qubits and spin ensembles are used, respectively, to process and store quantum information, while cavity photons induce an effective coupling between them, thus acting as a quantum bus [17,18].…”