Macroscopic quantum states: Measures, fragility, and implementations

F Fröwis, P Sekatski, W Dür, N Gisin… - Reviews of Modern Physics, 2018 - APS
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 …

Entanglement as the symmetric portion of correlated coherence

KC Tan, H Jeong - Physical review letters, 2018 - APS
We show that the symmetric portion of correlated coherence is always a valid quantifier of
entanglement, and that this property is independent of the particular choice of coherence …

Coherence, quantum Fisher information, superradiance, and entanglement as interconvertible resources

KC Tan, S Choi, H Kwon, H Jeong - Physical Review A, 2018 - APS
We demonstrate that quantum Fisher information and superradiance can be formulated as
coherence measures in accordance with the resource theory of coherence, thus establishing …

Quantum-error-correction-assisted quantum metrology without entanglement

KC Tan, S Omkar, H Jeong - Physical Review A, 2019 - APS
In this article we study the role that quantum resources play in quantum-error-correction-
assisted quantum metrology (QECQM) schemes. We show that there exist classes of such …

Coherence, asymmetry, and quantum macroscopicity

H Kwon, CY Park, KC Tan, D Ahn, H Jeong - Physical Review A, 2018 - APS
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 …

Connecting measurement invasiveness to optimal metrological scenarios

SV Moreira, G Adesso, LA Correa, T Coudreau… - Physical Review A, 2017 - APS
The connection between the Leggett-Garg inequality and optimal scenarios from the point of
view of quantum metrology is investigated for perfect and noisy general dichotomic …

Detecting macroscopic indefiniteness of cat states in bosonic interferometers

SP Kelly, E Timmermans, SW Tsai - Physical Review A, 2019 - APS
The paradigm of Schrödinger's cat illustrates how quantum states preclude the assignment
of definite properties to a macroscopic object (realism). In this work, we develop a method to …

Mesoscopic spin systems as quantum entanglers

MS Mirkamali, DG Cory - Physical Review A, 2020 - APS
We quantify the resources required for entangling two uncoupled spin qubits through an
intermediate mesoscopic spin system (MSS) by indirect joint measurement. Indirect joint …

Optimizing nontrivial quantum observables using coherence

KC Tan, S Choi, H Jeong - New Journal of Physics, 2019 - iopscience.iop.org
In this paper we consider the quantum resources required to maximize the mean values of
any nontrivial quantum observable. We show that the task of maximizing the mean value of …

Coherence-based characterization of macroscopic quantumness

M Naseri, S Raeisi - Physical Review A, 2021 - APS
One of the most elusive problems in quantum mechanics is the transition between classical
and quantum physics. This problem can be traced back to Schrödinger's cat thought …