Steering a quantum system over a Schroedinger bridge

Schrödinger's pure-state steering completed

Schroedinger investigated entanglement in two-particle state vectors by assuming measurement finding out if the nearby particle is in a given state vector or not. Without interaction with the distant particle, just on account of the entanglement, the distant particle is steered into a certain state vector. In Schroedinger's finite-dimensional case thus any distant-particle state vector can be reached. This theory was extended to infinite-dimensional spaces by the author. The present article completes the extension by throwing light on the fine structure of steering.

How Einstein and/or Schroedinger should have discovered Bell's theorem in 1936

This note shows how one can be led from considerations of quantum steering to Bell's theorem. The point is that steering remote systems by choosing between two measurements can be described in a local theory if we take quantum states to be associated many-to-one with the underlying "real states" of the world. Once one adds a third measurement this is no longer possible. Historically this is not how Bell's theorem arose - there are slight and subtle differences in the arguments - but it could have been.

Quantum Schroedinger bridges

Elaborating on M. Pavon, J.Math. Phys. 40 (1999), 5565-5577, we develop a simplified version of a variational principle within Nelson stochastic mechanics that produces the von Neumann wave packet reduction after a position measurement. This stochastic control problem parallels, with a different kinematics, the problem of the Schroedinger bridge. This gives a profound meaning to what was observed by Schroedinger in 1931 concerning Schroedinger bridges: "Merkwuerdige Analogien zur Quantenmechanik, die mir sehr des Hindenkens wert erscheinen".

Finite-time quantum-to-classical transition for a Schroedinger-cat state

The transition from quantum to classical, in the case of a quantum harmonic oscillator, is typically identified with the transition from a quantum superposition of macroscopically distinguishable states, such as the Schrödinger cat state, into the corresponding statistical mixture. This transition is commonly characterized by the asymptotic loss of the interference term in the Wigner representation of the cat state. In this paper we show that the quantum to classical transition has different dynamical features depending on the measure for nonclassicality used. Measures based on an operatorial …

基于混合光磁机械系统的多样量子纠缠操控

Manipulation of diverse quantum correlations based on a hybrid optomagnomechanical system

本文提出利用混合光磁机械系统生成和操控量子纠缠与引导，通过调整激光极化方向和Tavis-Cummings耦合强度，实现选择性生成双粒子和真实三粒子纠缠，并确定性操控双粒子、多粒子引导和集体五粒子引导。

半发射端设备无关量子密钥分发

Transmitter-device-independent quantum key distribution

本文提出一种半发射端设备无关量子密钥分发方案，通过构建可组合发射端，有效消除发射端依赖问题，实现首个离散变量1sDI-QKD，并在20公里光纤距离下获得1kbps安全密钥率，兼顾安全性和实用性。