Time-Domain-Multiplexed Measurement-Based Quantum Operations with 25-MHz Clock Frequency

Switching-free time-domain optical quantum computation with quantum teleportation

“…On the other hand, in the approach of using entanglement in this work, the CV quantum entanglement can be generated using only offline squeezed lights and passive linear optics and the switching of the measurement bases are done by changing the phases of the classical local oscillators which do not have the severe requirements regarding optical losses. In principle, the generation of the required quantum entanglement in time domain with sufficient quality is possible by extending the technology used in the cluster state generation and computation [8][9][10][11] and inclusion of high-quality squeezed light source [42]. Regarding the preparation of the GKP qubit which is required in most of the optical quantum computation architecture, although there are recent realizations in iontrapped system [43] and superconducting system [44] and the optical generation has not been achieved yet, there are a few promising theoretical proposals (see, for example Ref.…”

“…This additional entanglement structure can be used for injection of the input state, multiplexing/rerouting of the ancillary state, and coupling of the cluster states to the ancillary states in the error syndrome measurement. We can select and switch between each function by switching the measurement bases of the homodyne measurement, allowing these functions to be implemented in via quantum teleportation protocol.This removes the necessity of the inline active optical components, and the required offline active optical components are squeezed light sources and phase modulator for the local oscillators, which are both established technology [10,11]. We also perform a numerical calculation showing that depending on the quality of the optical switches, our system can realize a lower error probability when combined with Gottesman-Kitaev-Preskill (GKP) encoding [20].…”

“…Various researches have been done for both types and many different platforms have been theoretically developed and experimentally demonstrated [1,2]. From these various platforms, time-domain CV measurementbased quantum computation [3] has shown a great potential regarding scalability: large-scale universal computational resource-the cluster state [4,5]-has been generated [6][7][8][9] and basic operations on these scalable platform have also been demonstrated [10,11].…”

Analysis of optical quantum state preparation using photon detectors in the finite-temporal-resolution regime

“…In recent years, continuous variable optical quantum computation has been attracting attention due to its scalability. In fact, large-scale computational resources for measurement based quantum computation called cluster states have been generated by a time-domainmultiplexing method using continuous-wave (CW) light sources [1][2][3][4][5][6], and Gaussian operations using these cluster states have already been implemented [7,8]. On the other hand, one of the challenges in optical quantum computation is the preparation of non-Gaussian states necessary for error correction and universal operation [2,[9][10][11].…”

Generating Gottesman-Kitaev-Preskill qubit using a cross-Kerr interaction between a squeezed light and Fock states in optics

“…Recently, the single-and two-mode gates on a large-scale cluster state has been demonstrated in Refs. [15,16]. From these advantages, the GKP qubit is an indispensable resource for fault-tolerant quantum computation (FTQC) with CVs [11,[17][18][19][20][21].…”