Macroscopic quantum phenomena from the large N perspective

Abstract

Macroscopic quantum phenomena (MQP) is a relatively new research venue, with exciting ongoing experiments and bright prospects, yet with surprisingly little theoretical activity. What makes MQP intellectually stimulating is because it is counterpoised against the traditional view that macroscopic means classical. In this series of papers we report on a systematic investigation into some key foundational issues of MQP, with the hope of constructing a viable theoretical framework for this new endeavour. The three major themes discussed in these three essays are the large N expansion, the correlation hierarchy and quantum entanglement for systems of `large' sizes, with many components or degrees of freedom. In this paper we use different theories in a variety of contexts to examine the conditions or criteria whereby a macroscopic quantum system may take on classical attributes, and, more interestingly, that it keeps some of its quantum features. The theories we consider here are, the O(N) quantum mechanical model, semiclassical stochastic gravity and gauge / string theories; the contexts include that of a `quantum roll' in inflationary cosmology, entropy generation in quantum Vlasov equation for plasmas, the leading order and next-to-leading order large N behaviour, and hydrodynamic / thermodynamic limits. By examining different representative systems where detailed theoretical analysis has been carried out, we find that there is no a priori good reason why quantum phenomena in macroscopic objects cannot exist.

References in corpus (4)

• Entanglement of macroscopic test masses and the Standard Quantum Limit in laser interferometry
• Thermalization of an Interacting Quantum Field in the CTP-2PI Next-to-leading-order Large N Scheme
• Quantum Brownian Motion of a Macroscopic Object in a General Environment
• Gaussian Dynamics is Classical Dynamics

Cited by in corpus (10)

• Macroscopic quantum states: measures, fragility and implementations
• Linear dynamics of quantum-classical hybrids
• No intrinsic decoherence of inflationary cosmological perturbations
• Classical Dynamics Generated by Long-Range Interactions for Lattice Fermions and Quantum Spins
• Mirror-induced decoherence in hybrid quantum-classical theory
• Pathways toward understanding Macroscopic Quantum Phenomena
• Classical Dynamics from Self-Consistency Equations in Quantum Mechanics -- Extended Version
• Macroscopic Quantum Phenomena from the Coupling Pattern and Entanglement Structure Perspective
• Entanglement of Classical and Quantum Short-Range Dynamics in Mean-Field Systems
• Quantum Shape Effects