How squeezed states both maximize and minimize the same notion of quantumness
arXiv:2106.03862 · doi:10.1103/PhysRevA.104.032425
Abstract
Beam splitters are routinely used for generating entanglement between modes in the optical and microwave domains, requiring input states that are not convex combinations of coherent states. This leads to the ability to generate entanglement at a beam splitter as a notion of quantumness. A similar, yet distinct, notion of quantumness is the amount of entanglement generated by two-mode squeezers (i.e., four-wave mixers). We show that squeezed-vacuum states, paradoxically, both minimize and maximize these notions of quantumness, with the crucial resolution of the paradox hinging upon the relative phases between the input states and the devices. Our notion of quantumness is intrinsically related to eigenvalue equations involving creation and annihilation operators, governed by a set of inequalities that leads to generalized cat and squeezed-vacuum states.
12 pages including 2 figures and 1 appendix. Comments welcome!
References in corpus (15)
- QuTiP 2: A Python framework for the dynamics of open quantum systems
- Measuring Quantum Coherence with Entanglement
- Unconditional optimality of Gaussian attacks against continuous-variable QKD
- Optimality of Gaussian Attacks in Continuous Variable Quantum Cryptography
- A computable measure of nonclassicality for light
- General criterion for the entanglement of two indistinguishable particles
- All non-classical correlations can be activated into distillable entanglement
- Continuous-variable quantum cryptography is secure against non-gaussian attacks
- Entanglement in indistinguishable particle systems
- Entanglement of Gaussian states using beam splitter
- Purification of Single-photon Entanglement
- Quantum metrology at the Heisenberg limit with ion traps
- Entanglement Witnesses for Indistinguishable Particles
- Entanglement signature in the mode structure of a single photon
- Remarks on entanglement and identical particles