Proposal for Microwave Boson Sampling

Abstract

The first post-classical computation will most probably be performed not on a universal quantum computer, but rather on a dedicated quantum hardware. A strong candidate for achieving this is represented by the task of sampling from the output distribution of linear quantum optical networks. This problem, known as boson sampling, has recently been shown to be intractable for any classical computer, but it is naturally carried out by running the corresponding experiment. However, only small scale realizations of boson sampling experiments have been demonstrated to date. Their main limitation is related to the non-deterministic state preparation and inefficient measurement step. Here, we propose an alternative setup to implement boson sampling that is based on microwave photons and not on optical photons. The certified scalability of superconducting devices indicates that this direction is promising for a large-scale implementation of boson sampling and allows for more flexible features like arbitrary state preparation and efficient photon-number measurements.

Deterministic quantum nonlinear optics with single atoms and virtual photons

“…Indeed, the development of nonlinear optics with single photons has been the subject of much theoretical and experimental work recently due to the wealth of potential applications [58]. We note here that although our proposal does not use propagating waves, circuit QED setups with stationary photons that mimic linear-optics experiments for itinerant photons have already been proposed [59]. Several of the nonlinear-optics analogues given in the present work could be incorporated into such an architecture.…”

Towards quantum supremacy with lossy scattershot boson sampling

“…The same analysis conducted with quantum dot sources and an active demultiplexing approach reported a theoretical attainment of the bound with n 7 th  photons and m 50 th  modes. Aiming to maximize the efficiency and the accuracy of the protocol, we have finally analyzed a new suggestion by Peropadre et al [32] consisting in the adoption of on demand microwave photons. This proposal overcomes the problem of erroneous input states and provides a remarkable decrease of losses, thus enhancing the experimental rate.…”

“…Using feasible experimental parameters provided in [32], we can evaluate the threshold t t 1 c q > for a generalized version of BS with microwave photons. The calculations are similar to the ones for the case of optical photons without the issue of double pairs generation, but with the only constraint that the experimental rate is bounded by m s…”

Digital Quantum Simulation of Linear and Nonlinear Optical Elements

“…Therefore, our task would be to digitalize the Hamiltonian in Eq. (9). In this case we do not need to use the Suzuki-Trotter decomposition since we can directly leverage the Reck decomposition, which is standard in the boson sampling literature and entails that we can decompose the unitary evolution governed by H BS into a mesh of M (M − 1)/2 beam-splitters and appropriate phaseshifters.…”

“…Under certain conditions for the number of photons and modes, a boson sampling experiment would also prove quantum supremacy. However, while some smallscale experiments have been realised [5][6][7][8] and a number of promising proposals are available [9,10], a post-classical boson sampler has not yet been implemented in the laboratory. The ingredients needed in a boson sampling architecture are simple linear optics elements, such as beam-splitters and phase-shifters.…”