Experimental violation of a Bell’s inequality in time with weak measurement

2010/04/18 by Agustin Palacios-Laloy, F. Mallet, François Mallet +8 · 363 citations
Computer Science · Mathematics · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Bell state #Bell test experiments #Bell's theorem #CHSH inequality #Inequality #Local hidden variable theory #Mathematical analysis #Mathematics #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #Quantum nonlocality #Statistical physics #Theoretical physics #cond-mat.supr-con #quant-ph

paper · pdf · doi:10.1038/nphys1641

published in Nature Physics 6(6), 442-447 (Nature Portfolio) · 26 pages including 10 figures, preprint format

openalex publication_date 2010/04/18 · arxiv created 2010/05/19 · openalex created_date 2016/06/24 · arxiv updated 2016/11/27 · openalex updated_date 2026/08/05

Abstract

The violation of J. Bell's inequality with two entangled and spatially separated quantum two- level systems (TLS) is often considered as the most prominent demonstration that nature does not obey ?local realism?. Under different but related assumptions of "macrorealism", plausible for macroscopic systems, Leggett and Garg derived a similar inequality for a single degree of freedom undergoing coherent oscillations and being measured at successive times. Such a "Bell's inequality in time", which should be violated by a quantum TLS, is tested here. In this work, the TLS is a superconducting quantum circuit whose Rabi oscillations are continuously driven while it is continuously and weakly measured. The time correlations present at the detector output agree with quantum-mechanical predictions and violate the inequality by 5 standard deviations.

Citations

• Dynamics of a mesoscopic charge quantum bit under continuous quantum measurement
• Charge insensitive qubit design derived from the Cooper pair box
• Quantum trajectory approach to circuit QED: Quantum jumps and the Zeno effect
• Output spectrum of a measuring device at arbitrary voltage and temperature
• Quantum Zeno effect
• Continuous weak measurement of quantum coherent oscillations
• Experimental Realization of Einstein-Podolsky-Rosen-BohmGedankenexperiment: A New Violation of Bell's Inequalities
• ac Stark Shift and Dephasing of a Superconducting Qubit Strongly Coupled to a Cavity Field
• Cavity quantum electrodynamics for superconducting electrical circuits: An architecture for quantum computation
• Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics
• Violation of the Leggett–Garg inequality with weak measurements of photons

Cited by

• Identical, independent quantum weak measurements violate objective realism
• Gradually opening Schrödinger's box reveals a cascade of sharp dynamical transitions
• Leggett-Garg Inequality Violations Bound Quantum Fisher Information
• Multitime correlators in continuous measurement of qubit observables
• Quantum optical feedback control for creating strong correlations in many-body systems
• Canonical Leggett-Garg inequality: Nonclassicality of temporal quantum correlations under energy constraint
• Violations of the Leggett–Garg inequality for coherent and cat states
• Leggett-Garg inequalities and temporal correlations for a qubit under PT-symmetric dynamics
• Leggett-Garg tests of macrorealism for dynamical cat states evolving in a nonlinear medium
• Pedagogical Review of Quantum Measurement Theory with an Emphasis on Weak Measurements
• Experimental State Tomography of Itinerant Single Microwave Photons