Quantum Effects in Higher-Order Correlators of a Quantum-Dot Spin Qubit

We measure time correlators of a spin qubit in an optically active quantum dot beyond the second order. Such higher-order correlators are shown to be directly sensitive to pure quantum effects that cannot be explained within the classical framework. They allow direct determination of ensemble and qu...

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Bibliographic Details
Published in:Physical review letters 2016-07, Vol.117 (2), p.027402-027402, Article 027402
Main Authors: Bechtold, A, Li, F, Müller, K, Simmet, T, Ardelt, P-L, Finley, J J, Sinitsyn, N A
Format: Article
Language:English
Subjects:
Coherence
Correlators
Dynamical systems
Inequalities
Optical activity
Quantum dots
Qubits (quantum computing)
Spin dynamics
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Summary:We measure time correlators of a spin qubit in an optically active quantum dot beyond the second order. Such higher-order correlators are shown to be directly sensitive to pure quantum effects that cannot be explained within the classical framework. They allow direct determination of ensemble and quantum dephasing times, T_{2}^{*} and T_{2}, using only repeated projective measurements and without the need for coherent spin control. Our method enables studies of purely quantum behavior in solid state systems, including tests of the Leggett-Garg type of inequalities that rule out local hidden variable interpretation of the quantum-dot spin dynamics.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.117.027402