[Paper Review] Dissipative dynamics in particle physics

Raffaele Romano|ArXiv.org|Jun 18, 2003

Quantum Mechanics and Applications14 references4 citations

TL;DR

This thesis investigates dissipative dynamics in particle physics using open quantum systems formalism, focusing on Markovian semigroups to model decoherence and entropy production. It applies this framework to neutral B mesons, neutrinos, and neutron interferometry, deriving decay rates, asymmetries, and noncontextual inequalities, with key results showing how dissipative evolution affects CP violation and quantum coherence in these systems.

ABSTRACT

The subject of this thesis is the study of dissipative dynamics and their properties in particle physics, dealing with neutral B-mesons, neutron interferometry and neutrino physics. Modified expressions for the relevant phenomenological quantities characterizing these systems are obtained. Moreover, the models presented in this work offer the possibility of direct tests of some basic properties of reduced dynamics (in particular the notion of complete positivity) since they represent concrete systems amenable to actual experiments.

Motivation & Objective

• To develop a theoretical framework for dissipative dynamics in particle physics using open quantum systems and Markovian semigroups.
• To analyze how environment-induced decoherence affects CP violation and decay asymmetries in neutral B mesons.
• To investigate flavor-changing dissipative evolution in neutrinos under varying matter densities.
• To test noncontextuality in neutron interferometry using stochastic thermal baths with different correlation structures.
• To ensure physical consistency of the dynamics by enforcing complete positivity of the evolution maps.

Proposed method

• Formalizing open quantum systems via reduced dynamics derived from unitary evolution of system-plus-environment, leading to Markovian semigroups.
• Applying the weak coupling limit and factorized initial conditions to derive the generalized master equation and generator of the dynamical semigroup.
• Using the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) form to ensure complete positivity and physical consistency of the time evolution.
• Constructing stochastic models of thermal baths with white noise, diagonal covariance, and single-component field correlations for neutron interferometry.
• Evaluating noncontextuality via the Clauser-Horne-Shimony-Holt (CHSH) inequality under different stochastic backgrounds.
• Deriving explicit expressions for density matrix elements and observables in the eigenstate basis for B mesons and neutrinos.

Experimental results

Research questions

• RQ1 How does dissipative dynamics affect the decay rates and CP asymmetries in single and entangled B mesons?
• RQ2 Can flavor-changing dissipative evolution in neutrinos lead to observable deviations from standard oscillation patterns in matter?
• RQ3 What are the implications of different stochastic bath correlations (white noise, diagonal, single-component) on noncontextuality in neutron interferometry?
• RQ4 Under what conditions does the dissipative evolution preserve complete positivity and physical consistency in open quantum systems?
• RQ5 How does the Markovian approximation break down or remain valid in the presence of memory effects in particle decay processes?

Key findings

• The dissipative evolution of neutral B mesons leads to modified decay rates and asymmetries that depend on the dissipative parameters in the GKSL generator.
• For entangled B meson pairs, the dissipative dynamics induces non-trivial correlations in decay asymmetries, altering standard CP violation measurements.
• In the neutrino case, the dissipative generator leads to flavor-changing transitions even in vacuum, with deviations scaling with the dissipative coupling strength.
• In neutron interferometry, the CHSH inequality is violated under white noise and diagonal covariance matrix backgrounds, indicating contextuality, while the single-component field correlation case shows reduced or no violation.
• The conditions for complete positivity are explicitly checked and found to be satisfied when the dissipative parameters are properly constrained in the eigenstate basis.
• The time evolution of density matrices for B mesons is derived in closed form using stochastic operators, showing explicit dependence on initial state and bath correlation functions.