A measurement-based measure of the size of macroscopic quantum superpositions
arXiv:quant-ph/0611121 · doi:10.1103/PhysRevA.75.042106
Abstract
Recent experiments claiming formation of quantum superposition states in near macroscopic sys- tems raise the question of how the sizes of general quantum superposition states in an interacting system are to be quantified. We propose here a measure of size for such superposition states that is based on what measurements can be performed to probe and distinguish the different branches of the state. The measure allows comparison of the effective size for superposition states in very different physical systems. It can be applied to a very general class of superposition states and reproduces known results for near-ideal cases. Comparison with a prior measure based on analy- sis of coherence between branches indicates that significantly smaller effective superposition sizes result from our measurement-based measure. Application to a system of interacting bosons in a double-well trapping potential shows that the effective superposition size is strongly dependent on the relative magnitude of the barrier height and interparticle interaction.
21 pages, 20 figures. Accepted by Phys. Rev. A. Replaced old version with accepted version. Significant changes and improvements, particularly to section on 1-particle measurements
References in corpus (2)
Cited by in corpus (24)
- Quantum Decoherence
- Testing the limits of quantum mechanical superpositions
- Macroscopicity of Mechanical Quantum Superposition States
- Measures of macroscopicity for quantum spin systems
- Quantification of Macroscopic Quantum Superpositions within Phase Space
- Necessary and sufficient conditions for macroscopic realism from quantum mechanics
- Measuring the size of a Schroedinger cat state
- Robust Mesoscopic Superposition of Strongly Correlated Ultracold Atoms
- Linking Measures for Macroscopic Quantum States via Photon-Spin Mapping
- Characterizations and Quantifications of Macroscopic Quantumness and Its Implementations using Optical Fields
- Criteria for generalized macroscopic and mesoscopic quantum coherence
- Quantifying the mesoscopic quantum coherence of approximate NOON states and spin-squeezed two-mode Bose-Einstein condensates
- Reversal of the circulation of a vortex by quantum tunneling in trapped Bose systems
- Assessments of macroscopicity for quantum optical states
- Are cloned quantum states macroscopic?
- Decoherence of Highly Mixed Macroscopic Quantum Superpositions
- Lower bounds on the size of general Schrödinger-cat states from experimental data
- Macroscopicity of quantum superpositions on a one-parameter unitary path in Hilbert space
- Correlated Worldline theory: Structure and Consistency
- Identifying Quantum Topological Phases Through Statistical Correlation
- Sequentially generated entanglement, macroscopicity and squeezing in a spin chain
- Quantum Biology at the Cellular Level - elements of the research program
- How many lives does Schrödinger's cat have?
- Coherence Based Characterization of Macroscopic Quantumness