# Subtleties of witnessing quantum coherence in nonisolated systems

@article{Knee2018SubtletiesOW, title={Subtleties of witnessing quantum coherence in nonisolated systems}, author={George C Knee and Max Marcus and Luke D. Smith and Animesh Datta}, journal={Physical Review A}, year={2018}, volume={98}, pages={052328} }

Identifying nonclassicality unambiguously and inexpensively is a long-standing open challenge in physics. The no-signaling-in-time protocol was developed as an experimental test for macroscopic realism, and serves as a witness of quantum coherence in isolated quantum systems by comparing the quantum state to its completely dephased counterpart. We show that it provides a lower bound on a certain resource-theoretic coherence monotone. We go on to generalize the protocol to the case where the… Expand

#### 10 Citations

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The authors provide a quantitative measure of non-classicality for purely dephasing evolutions, and illustrate the method for qubit, qutrit, and qubit-pair pure dephase and describe how to implement it with quantum process tomography experiments. Expand

Witnessing non-objectivity in the framework of strong quantum Darwinism

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Quantum Darwinism is a compelling theory that describes the emergence of objectivity of quantum systems. Spectrum broadcast structure and strong quantum Darwinism are two extensions of quantum… Expand

Experimental test of non-macrorealistic cat states in the cloud

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The Leggett–Garg inequality attempts to classify experimental outcomes as arising from one of two possible classes of physical theories: those described by macrorealism (which obey our intuition… Expand

Investigating nonclassicality in nonlinear electronic spectroscopy

- Physics, Mathematics
- 2018

In this work, we establish a connection between nonlinear electronic spectroscopy and quantum information protocols for the non-disturbance condition. The non-fulfillment of the later is a witness of… Expand

Leggett-Garg macrorealism and the quantum nondisturbance conditions

- Physics
- Physical Review A
- 2019

We investigate the relation between a refined version of Leggett and Garg conditions for macrorealism, namely the no-signaling-in-time (NSIT) conditions, and the quantum mechanical notion of… Expand

Estimating quantum coherence by noncommutativity of any observable and its incoherent part

- Physics
- 2020

We establish an inequality involving the quantum coherence of an arbitrary quantum state, possibly nonpure, in arbitrary dimension and a noncommutativity estimator of an arbitrary observable. The… Expand

Towards a spectroscopic protocol for unambiguous detection of quantum coherence in excitonic energy transport.

- Mathematics, Physics
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- 2019

This work proposes a witness for quantum coherence in EET that can be extracted directly from two-pulse pump-probe spectroscopy experimental data and provides simulations to judge the feasibility of this approach. Expand

Validating and controlling quantum enhancement against noise by the motion of a qubit

- Physics
- 2020

Experimental validation and control of quantum traits for an open quantum system are important for any quantum information purpose. We consider a traveling atom qubit as a quantum memory with… Expand

Leggett-Garg tests of macrorealism: Checks for noninvasiveness and generalizations to higher-order correlators

- Physics
- 2019

In the tests for macrorealism proposed by Leggett and Garg, the temporal correlation functions of a dichotomic variable Q must be measured in a non-invasive way to rule out alternative classical… Expand

Monitoring the evolution of intersite and interexciton coherence in electronic excitation transfer via wave-packet interferometry.

- Medicine, Physics
- The Journal of chemical physics
- 2020

Detailed theoretical expressions for the desired WPI signal are exhibited, the physical origin of electronic coherence detection is explained, and calculated observed-coherence signals for model dimers with one, two, or three internal vibrational modes per monomer and both weak and strong energy-transfer coupling are shown. Expand

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