Fully passive polarization quantum state chromatography method and chip

Abstract

The invention discloses a fully passive polarization quantum state chromatography method and a chip. The method comprises the steps: 1) converting polarization information of a to-be-measured optical signal into path information by using an on-chip integrated polarization-path converter, and respectively outputting the path information through 2n paths of waveguides; 2) leading out an optical signal in each path of waveguide to 3n paths through an on-chip integrated multimode interference device and waveguide crossers, and dividing path information into 6n paths of output light; 3) combining every two output lights on the 6n paths into 3n identical input quantum states by using the waveguide crossers; 4) dividing each input quantum state into two paths of output, measuring each path of output through an on-chip integrated superconducting single-photon detector, and achieving measurement of the input quantum states under any two-dimensional unitary matrix projection basis vector; and 5) fitting a measurement result to reconstruct a density matrix of the quantum states, and realizing the chromatographic measurement of the quantum state. According to the method, the complex quantum state chromatography process is simplified, full automation is achieved, and high expansibility is achieved.

Description

technical field [0001] The invention relates to the field of quantum chips, specifically a method of converting the polarization information of the light quantum state into path information by using an on-chip polarization beam splitter and rotator, and performing single-chip integration with an on-chip superconducting nanowire single-photon detector, which can perform polarization A chip design in which the quantum state is directly subjected to quantum tomography and the result is output directly. Background technique [0002] Polarization-encoded optical qubits load quantum information on polarization information, which has the advantages of simple preparation, convenient manipulation, and excellent performance. It has a wide range of applications in the fields of quantum secret key distribution, quantum computing, and quantum information. Accurate detection and measurement of optical qubits is of great significance to the completion of quantum information processing, tra...

AI Technical Summary

Problems solved by technology

[0003] In order to achieve quantum state tomography in traditional methods, complex tunable optical devices and a large number of data collection and analysis devices are required, and its redundant control and measurement methods greatly limit the scalability and practicability of its quantum information system

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