Colloquium: Time-reversal violation with quantum-entangled B mesons

Abstract

Symmetry transformations have been proven a bedrock tool for understanding the nature of particle interactions, formulating and testing fundamental theories. Based on the up to now unbroken CPT symmetry, the violation of the CP symmetry between matter and antimatter by weak interactions, discovered in the decay of kaons in 1964 and observed more recently in 2001 in B mesons, strongly suggests that the behavior of these particles under weak interactions must also be asymmetric under time reversal T. However, until the recent years there has not been a direct detection of the expected time-reversal violation in the time evolution of any system. This Colloquium examines the field of time-reversal symmetry breaking in the fundamental laws of physics. For transitions, its observation requires an asymmetry with exchange of initial and final states. We discuss the conceptual basis for such an exchange with unstable particles, using the quantum properties of Einstein Podolsky-Rosen (EPR) entanglement available at B meson factories combined with the decay as a filtering measurement. The method allows a clear-cut separation of different transitions between flavor and CP eigenstates in the decay of neutral B mesons. These ideas have been implemented for the experiment by the BaBar Collaboration at SLAC's B factory. The results, presented in 2012, prove beyond any doubt the violation of time-reversal invariance in the time evolution between these two states of the neutral B meson.

arXiv comment20 pages, 18 figures, submitted to Reviews of Modern Physics Colloquia

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Cited by in corpus (11)

• Testing CPT symmetry in ortho-positronium decays with positronium annihilation tomography
• Entangled baryons: violation of Inequalities based on local realism assuming dependence of decays on hidden variables
• Time reversal symmetry violation in entangled pseudoscalar neutral charmed mesons
• Cartan's Supersymmetry and the violation of CP symmetry
• Polarization in (quasi-)two-body decays and new physics
• Time-reversal-symmetry bounds on electromagnetic fields
• Feasibility study of the time reversal symmetry tests in decays of metastable positronium atoms with the J-PET detector
• Threshold and infrared singularities: time evolution, asymptotic state and entanglement entropy
• Time Reversal Invariance in Quantum Mechanics
• Refined Applications of the "Collapse of the Wavefunction"
• Probing CPT in transitions with entangled neutral kaons