# Characterizations and Quantifications of Macroscopic Quantumness and Its Implementations using Optical Fields

@article{Jeong2015CharacterizationsAQ, title={Characterizations and Quantifications of Macroscopic Quantumness and Its Implementations using Optical Fields}, author={Hyunseok Jeong and Minsu Kang and Hyukjoon Kwon}, journal={Optics Communications}, year={2015}, volume={337}, pages={12-21} }

## 26 Citations

Macroscopic quantum states: Measures, fragility, and implementations

- PhysicsReviews of Modern Physics
- 2018

Large-scale quantum effects have always played an important role in the foundations of quantum theory. With recent experimental progress and the aspiration for quantum enhanced applications, the…

Detecting the degree of macroscopic quantumness using an overlap measurement

- Physics
- 2014

We investigate how to experimentally detect a recently proposed measure to quantify macroscopic quantum superpositions [Phys. Rev. Lett.106, 220401…

Coherence, asymmetry, and quantum macroscopicity

- Physics
- 2018

We investigate a measure of quantum coherence and its extension to quantify quantum macroscopicity. The coherence measure can also quantify the asymmetry of a quantum state with respect to a given…

Coherent Superpositions of Photon Creation Operations and Their Application to Multimode States of Light

- PhysicsEntropy
- 2021

A concise review of recent experimental results concerning the conditional implementation of coherent superpositions of single-photon additions onto distinct field modes shows the generation of a tunable degree of entanglement and peculiar correlations in the photon numbers and the quadratures of multimode, multiphoton, states of light.

Macroscopic Superpositions as Quantum Ground States.

- PhysicsPhysical review letters
- 2017

An upper bound on the energy gap of an arbitrary physical Hamiltonian provided that its ground state is a superposition of two well-distinguishable macroscopic "semiclassical" states is derived.

Quantum Apices: Identifying Limits of Entanglement, Nonlocality, & Contextuality

- Physics
- 2014

This work develops analytic methods to quantitatively demarcate quantum reality from its subset of classical phenomenon, as well as from the superset of general probabilistic theories. Regarding…

Entangling Macroscopic Light States by Delocalized Photon Addition.

- PhysicsPhysical review letters
- 2020

A high degree of entanglement can in principle endure light states of macroscopic intensities and is expected to be particularly robust against losses.

Quantum metrology with generalized cat states

- PhysicsPhysical Review A
- 2019

We show a general relationship between a superposition of macroscopically distinct states and sensitivity in quantum metrology. Generalized cat states are defined by using an index which extracts the…

Quantum violation of classical physics in macroscopic systems

- Physics
- 2016

While quantum theory has been tested to an incredible degree on microscopic scales, quantum effects are seldom observed in our everyday macroscopic world. The curious results of applying quantum…

## References

SHOWING 1-10 OF 323 REFERENCES

Quantification of macroscopic quantum superpositions within phase space.

- PhysicsPhysical review letters
- 2011

This measure simultaneously quantifies two different kinds of essential information for a given quantum state in a harmonious manner: the degree of quantum coherence and the effective size of the physical system that involves the superposition.

Detecting the degree of macroscopic quantumness using an overlap measurement

- Physics
- 2014

We investigate how to experimentally detect a recently proposed measure to quantify macroscopic quantum superpositions [Phys. Rev. Lett.106, 220401…

Quantum superpositions and entanglement of thermal states at high temperatures and their applications to quantum-information processing

- Physics
- 2007

We study characteristics of superpositions and entanglement of thermal states at high temperatures and discuss their applications to quantum-information processing. We introduce thermal-state qubits…

Optical hybrid approaches to quantum information

- Physics
- 2010

This article reviews recent hybrid approaches to optical quantum information processing, in which both discrete and continuous degrees of freedom are exploited, potentially adding weak or measurement-induced nonlinearities to the toolbox.

Measures of macroscopicity for quantum spin systems

- Physics
- 2012

We investigate the notion of ‘macroscopicity’ in the case of quantum spin systems and provide two main results. Firstly, we motivate the quantum Fisher information as a measure of the macroscopicity…

Elementary gates for quantum information with superposed coherent states

- Physics
- 2010

We propose an alternative way of implementing several elementary quantum gates for qubits in the coherent-state basis. The operations are probabilistic and employ single-photon subtractions as the…

Polarization properties of macroscopic Bell states

- Physics
- 2011

The four two-photon polarization Bell states are one of the main instruments in the toolbox of quantum optics and quantum information. In our experiment we produce their multiphoton counterparts,…

Macroscopicity of mechanical quantum superposition states.

- PhysicsPhysical review letters
- 2013

We propose an experimentally accessible, objective measure for the macroscopicity of superposition states in mechanical quantum systems. Based on the observable consequences of a minimal,…