Hyper-parallel photonic quantum computation with coupled quantum dots

TL;DR

This paper proposes a scalable hyper-parallel quantum computation method using two degrees of freedom of photons, constructing a deterministic hyper-CNOT gate with quantum-dot spins in microcavities, enhancing efficiency and robustness.

Contribution

It introduces a novel hyper-CNOT gate operating on both spatial-mode and polarization DOFs of photons, enabling scalable and resource-efficient quantum computation.

Findings

The hyper-CNOT gate operates deterministically without auxiliary modes.

It reduces operation time and resource consumption.

It is more robust against photonic dissipation noise.

Abstract

It is well known that a parallel quantum computer is more powerful than a classical one. So far, there are some important works about the construction of universal quantum logic gates, the key elements in quantum computation. However, they are focused on operating on one degree of freedom (DOF) of quantum systems. Here, we investigate the possibility of achieving scalable hyper-parallel quantum computation based on two DOFs of photon systems. We construct a deterministic hyper-controlled-not (hyper-CNOT) gate operating on both the spatial-mode and the polarization DOFs of a two-photon system simultaneously, by exploiting the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics (QED). This hyper-CNOT gate is implemented by manipulating the four qubits in the two DOFs of a two-photon system without auxiliary spatial modes or polarization modes. It reduces the operation time and the resources consumed in quantum information processing, and it is more robust against the photonic dissipation noise, compared with the integration of several cascaded CNOT gates in one DOF.