Quantum Cryptography with Orthogonal States?

This is a Comment on Phys Rev Lett 75 (1995) 1239, by Goldenberg and VaidmanComment: 3 pages, LaTeX, 1 figure on separate page Final version in Phys Rev Lett 77 (1996) 326

Thermodynamics and the Measure of Entanglement

We point out formal correspondences between thermodynamics and entanglement. By applying them to previous work, we show that entropy of entanglement is the unique measure of entanglement for pure states.Comment: 8 pages, RevTeX; edited for clarity, additional references, to appear as a Rapid Communication in Phys. Rev.

Workshop on Applications of Phase Diagrams in Metallurgy and Ceramics

A workshop was held to assess the current national and international status of phase diagram determinations and evaluations for alloys, ceramics, and semiconductors; to determine the needs and priorities, especially technological, for phase diagram determinations and evaluations; and to estimate the resources being used and potentially available for phase diagram evaluation. Highlights of the workshop, description of a new poster board design used in the poster sessions, lists of attendees and demonstrations, the program, and descriptions of the presentations are included

Fatigue testing of low-cost fiberglass composite wind turbine blade materials

The static and fatigue behavior of transverse filament tape (TFT) fiberglass/epoxy and TFT/polyester composites was established by the testing of specimens cut from panels fabricated by a filament winding process used for the construction of large experimental wind turbine blades

The Parity Bit in Quantum Cryptography

An $n$-bit string is encoded as a sequence of non-orthogonal quantum states. The parity bit of that $n$-bit string is described by one of two density matrices, $\rho_0^{(n)}$ and $\rho_1^{(n)}$, both in a Hilbert space of dimension $2^n$. In order to derive the parity bit the receiver must distinguish between the two density matrices, e.g., in terms of optimal mutual information. In this paper we find the measurement which provides the optimal mutual information about the parity bit and calculate that information. We prove that this information decreases exponentially with the length of the string in the case where the single bit states are almost fully overlapping. We believe this result will be useful in proving the ultimate security of quantum crytography in the presence of noise.Comment: 19 pages, RevTe

Inhibition of the Aminopeptidase from \u3cem\u3eAeromonas proteolytica\u3c/em\u3e by l-leucinethiol: Kinetic and Spectroscopic Characterization of a Slow, Tight-binding Inhibitor–enzyme Complex

The peptide inhibitor l-leucinethiol (LeuSH) was found to be a potent, slow-binding inhibitor of the aminopeptidase from Aeromonas proteolytica (AAP). The overall potency (KI*) of LeuSH was 7 nM while the corresponding alcohol l-leucinol (LeuOH) was a simple competitive inhibitor of much lower potency (KI=17 μM). These data suggest that the free thiol is likely involved in the formation of the E·I and E·I* complexes, presumably providing a metal ligand. In order to probe the nature of the interaction of LeuSH and LeuOH with the dinuclear active site of AAP, we have recorded both the electronic absorption and EPR spectra of [CoCo(AAP)], [CoZn(AAP)], and [ZnCo(AAP)] in the presence of both inhibitors. In the presence of LeuSH, all three Co(II)-substituted AAP enzymes exhibited an absorption band centered at 295 nm, characteristic of a S→Co(II) ligand-metal charge-transfer band. In addition, absorption spectra recorded in the 450 to 700 nm region all showed changes characteristic of LeuSH and LeuOH interacting with both metal ions. EPR spectra recorded at high temperature (19 K) and low power (2.5 mW) indicated that, in a given enzyme molecule, LeuSH interacts weakly with one of the metal ions in the dinuclear site and that the crystallographically identified μ-OH(H) bridge, which has been shown to mediate electronic interaction of the Co(II) ions, is likely broken upon binding LeuSH. EPR spectra of [CoCo(AAP)]-LeuSH, [ZnCo(AAP)]-LeuSH, and [Co_(AAP)]-LeuSH were also recorded at lower temperature (3.5–4.0 K) and high microwave power (50–553 mW). These signals were unusual and appeared to contain, in addition to the incompletely saturated contributions from the signals characterized at 19 K, a very sharp feature at geff∼6.5 that is characteristic of thiolate-Co(II) interactions. Combination of the electronic absorption and EPR data indicates that LeuSH perturbs the electronic structure of both metal ions in the dinuclear active site of AAP. Since the spin–spin interaction seen in resting [CoCo(AAP)] is abolished upon the addition of LeuSH, it is unlikely that a μ-S(R) bridge is established