Microcanonical Origin of the Maximum Entropy Principle for Open Systems

The canonical ensemble describes an open system in equilibrium with a heat bath of fixed temperature. The probability distribution of such a system, the Boltzmann distribution, is derived from the uniform probability distribution of the closed universe consisting of the open system and the heat bath, by taking the limit where the heat bath is much larger than the system of interest. Alternatively, the Boltzmann distribution can be derived from the Maximum Entropy Principle, where the Gibbs-Shannon entropy is maximized under the constraint that the mean energy of the open system is fixed. To make the connection between these two apparently distinct methods for deriving the Boltzmann distribution, it is first shown that the uniform distribution for a microcanonical distribution is obtained from the Maximum Entropy Principle applied to a closed system. Then I show that the target function in the Maximum Entropy Principle for the open system, is obtained by partial maximization of Gibbs-Shannon entropy of the closed universe over the microstate probability distributions of the heat bath. Thus, microcanonical origin of the Entropy Maximization procedure for an open system, is established in a rigorous manner, showing the equivalence between apparently two distinct approaches for deriving the Boltzmann distribution. By extending the mathematical formalism to dynamical paths, the result may also provide an alternative justification for the principle of path entropy maximization as well.Comment: 12 pages, no figur

Normal mode splitting and mechanical effects of an optical lattice in a ring cavity

A novel regime of atom-cavity physics is explored, arising when large atom samples dispersively interact with high-finesse optical cavities. A stable far detuned optical lattice of several million rubidium atoms is formed inside an optical ring resonator by coupling equal amounts of laser light to each propagation direction of a longitudinal cavity mode. An adjacent longitudinal mode, detunedby about 3 GHz, is used to perform probe transmission spectroscopy of the system. The atom-cavity coupling for the lattice beams and the probe is dispersive and dissipation results only from the finite photon-storage time. The observation of two well-resolved normal modes demonstrates the regime of strong cooperative coupling. The details of the normal mode spectrum reveal mechanical effects associated with the retroaction of the probe upon the optical lattice.Comment: 4 pages, 3 figure

Julian Jaynes, Graduate Commencement Speaker, 1979

https://digitalcommons.ric.edu/av_root/1139/thumbnail.jp

In vitro cytocidal effect of lytic peptides on several transformed mammalian cell lines.

Several types of transformed mammalian cells, derived from established cell lines, were found to be lysed in vitro by three novel lytic peptides (SB-37, SB-37*, and Shiva-1). This is in contrast with the behavior of normal cells, where the observed lytic activity of the peptides is greatly reduced. Based on experiments utilizing compounds which disrupt the cytoskeleton (colchicine and cytochalasin-D), it is surmised that alterations in the cytoskeleton of transformed cells increase their sensitivity to the cytolytic activity exerted by the peptides, primarily by causing a loss of osmotic integrity. Thus, a stable and regenerative cytoskeletal system, as that possessed by normal cells, would seem requisite to withstanding the lytic effects of the peptides