From Liouville equation to universal quantum control: A study of generating ultra highly squeezed states

TL;DR

This paper unifies classical and quantum control methods via differential manifolds, enabling the generation of ultra highly squeezed states through nonadiabatic passages guided by ancillary canonical variables.

Contribution

It introduces a unified framework connecting classical and quantum control approaches and demonstrates the generation of highly squeezed states using non-Hermitian Hamiltonians.

Findings

Achieved 29.3 dB single-mode squeezing.

Generated 20.5 dB double-mode squeezing.

Unified classical and quantum control via ancillary representations.

Abstract

Within a unified framework, we reveal that the seemingly disparate control approaches for classical and quantum continuous-variable systems are interconnected via differential manifolds of the ancillary representations. For classical systems, the ancillary representation is defined by the time-dependent ancillary canonical variables resulting from a symplectic transformation over the original canonical variables. Under the conditions of the Hamilton-Jacobi equation, the ancillary canonical variables act as dynamical invariants to guide the system nonadiabatically through the entire phase space. The second quantization of the Liouville equation for the canonical variables leads to the Heisenberg equation for the relevant ancillary operators, which is found to be a sufficient condition to yield nonadiabatic passages towards arbitrary target states in both Hermitian and non-Hermitian systems and constrained exact solutions of the time-dependent Schroedinger equation. Using the non-Hermitian Hamiltonian rigorously derived from the Lindblad master equation, our theory is exemplified by the generation of single-mode squeezed states with a squeezing level of 29.3 dB and double-mode squeezed states with 20.5 dB, respectively.