Two ocean acoustics experiments demonstrating the implementation of a time reversal mirror have been conducted. Pulsed sound (50-ms with center frequency 445 Hz) was refocused to the position of a probe source out to ranges as great as 30 km in 125-m deep water. In addition, a technique to refocus at ranges other than that of the probe source also was demonstrated. These results are summarized ...

There are two types of Asian options in the financial markets which differ according to the role of the average price. We give a symmetry result between the floating and fixed-strike Asian options. The proof involves a change of numéraire and time reversal of Brownian motion. Symmetries are very useful in option valuation and in this case, the result allows the use of more established fixed-str...

Advantages of investigation of time reversal invariance violation with the use of three-fold (P,T-odd) and five-fold (P-even,T-odd) correlations in the interaction of resonance neutrons with nuclei are briefly considered. Possible enhancements of T-odd effects in both cases are discussed. It is shown that the study of five-fold correlation is a perspective way to test time reversal invariance. ...

Although most fundamental laws are invariant under time reversal, experience exhibits the presence of irreversible phenomena – the arrows of time. Their origin lies in cosmology, and I argue that only quantum cosmology can provide the appropriate formal framework. After briefly reviewing the formalism, I discuss how a simple and natural boundary condition can lead to the observed arrows of time...

In a recent paper, Malament (2004) employs a time reversal transformation that differs from the standard one, without explicitly arguing for it. This is a new and important understanding of time reversal that deserves arguing for in its own right. I argue that it improves upon the standard one. Recent discussion has focused on whether velocities should undergo a time reversal operation. I addre...

Understanding the allocation of skilled labor across industries is necessary to explain inter-industry wage differences and the effect of trade on wages. This paper develops an assignment model with both labor and non-labor inputs in which the assignment of heterogeneous labor across sectors is driven by variation in non-labor input productivity. A scale of operations effect causes high skill a...

The dynamics of an open quantum system can be described by a quantum operation: A linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal i...

We analyze the implementation of the time-reversal (TR) transformation in the algebraic approach to tetrahedral local molecules through the chain of groups U(5) ⊃ U(4) ⊃ K(4) = A(4) ∧ S(4) ⊃ S(4) ≈ Td. We determine the general form of the TR operation using a purely algebraic realization, based exclusively on the requirement that the irreducible representations must not be changed under the tim...