Time's Arrow and the Measurement Problem

Jean Paul Van Bendegem

Zhen Wang

A generalized framework is developed which uses a set description instead of wavefunction to emphasize the role of the observer. Such a framework is found to be very effective in the study of the measurement problem and time's arrow. Measurement in classical and quantum theory is given a unified treatment. With the introduction of the concept of uncertainty quantum which is the basic unit of measurement, we show that the time's arrow within the uncertainty quantum is just opposite to the time's arrow in the observable reality. A special constant is discussed which explains our sensation of time and provides a permanent substrate for all change. It is shown that the whole spacetime connects together in a delicate structure.

Maitreyi Jayaseelan, Sreenath K. Manikandan, Andrew N. Jordan +1 more

The origin of macroscopic irreversibility from microscopically time-reversible dynamical laws-often called the arrow-of-time problem-is of fundamental interest in both science and philosophy. Experimentally probing such questions in quantum theory requires systems with near-perfect isolation from the environment and long coherence times. Ultracold atoms are uniquely suited to this task. We experimentally demonstrate a striking parallel between the statistical irreversibility of wavefunction collapse and the arrow of time problem in the weak measurement of the quantum spin of an atomic cloud. Our experiments include statistically rare events where the arrow of time is inferred backward; nevertheless we provide evidence for absolute irreversibility and a strictly positive average arrow of time for the measurement process, captured by a fluctuation theorem. We further demonstrate absolute irreversibility for measurements performed on a quantum many-body entangled wavefunction-a unique opportunity afforded by our platform-with implications for studying quantum many-body dynamics and quantum thermodynamics.

Shan Gao

Szabó, László

WU Xin-zhong

It is inconsistent between the irreversible process of wave-packet collapse in quantum measurement and the reversibility of quantum mechanics characterized by Schrdinger Equation.The conflict is the origin of measurement problem of quantum mechanics.How to solve the inconsistency concerns the understanding of some philosophical concepts.