Operator-Schmidt decomposition of the quantum Fourier transform on C^N1 tensor C^N2

Operator-Schmidt decompositions of the quantum Fourier transform on C^N1 tensor C^N2 are computed for all N1, N2 > 1. The decomposition is shown to be completely degenerate when N1 is a factor of N2 and when N1>N2. The first known special case, N1=N2=2^n, was computed by Nielsen in his study of the communication cost of computing the quantum Fourier transform of a collection of qubits equally distributed between two parties. [M. A. Nielsen, PhD Thesis, University of New Mexico (1998), Chapter 6, arXiv:quant-ph/0011036.] More generally, the special case N1=2^n1<2^n2=N2 was computed by Nielsen et. al. in their study of strength measures of quantum operations. [M.A. Nielsen et. al, (accepted for publication in Phys Rev A); arXiv:quant-ph/0208077.] Given the Schmidt decompositions presented here, it follows that in all cases the communication cost of exact computation of the quantum Fourier transform is maximal.Comment: 9 pages, LaTeX 2e; No changes in results. References and acknowledgments added. Changes in presentation added to satisfy referees: expanded introduction, inclusion of ommitted algebraic steps in the appendix, addition of clarifying footnote

DsJD_{sJ}(2317) meson production at RHIC

Production of $D_{sJ}$(2317) mesons in relativistic heavy ion collisions at RHIC is studied. Using the quark coalescence model, we first determine the initial number of $D_{sJ}$(2317) mesons produced during hadronization of created quark-gluon plasma. The predicted $D_{sJ}$(2317) abundance depends sensitively on the quark structure of the $D_{sJ}$(2317) meson. An order-of-magnitude larger yield is obtained for a conventional two-quark than for an exotic four-quark $D_{sJ}$(2317) meson. To include the hadronic effect on the $D_{sJ}$(2317) meson yield, we have evaluated the absorption cross sections of the $D_{sJ}$(2317) meson by pion, rho, anti-kaon, and vector anti-kaon in a phenomenological hadronic model. Taking into consideration the absorption and production of $D_{sJ}$(2317) mesons during the hadronic stage of heavy ion collisions via a kinetic model, we find that the final yield of $D_{sJ}$(2317) mesons remains sensitive to its initial number produced from the quark-gluon plasma, providing thus the possibility of studying the quark structure of the $D_{sJ}$(2317) meson and its production mechanism in relativistic heavy ion collisions.Comment: 12 pages, 6 figure

Erratum: QCD sum rules study of the JPC=1−−J^{PC}=1^{--} charmonium YY mesons

We correct a mistake in the analytical expression given in Nucl. Phys. {\bf A} 815, 53 (2009) [arXiv:0804.4817] for the $D_{s0}\bar{D}_s^*$ and $D_{0}\bar{D}^*$ molecular currents. As a consequence, the mass obtained for the $D_{0}\bar{D}^*$ molecular current: $m_{D_{0}\bar{D}^*}=(4.96\pm 0.11)$ GeV is no longer compatible with the experimental mass of the meson Y(4260).Comment: 1 pag

Toward a more economical cluster state quantum computation

We assess the effects of an intrinsic model for imperfections in cluster states by introducing {\it noisy cluster states} and characterizing their role in the one-way model for quantum computation. The action of individual dephasing channels on cluster qubits is also studied. We show that the effect of non-idealities is limited by using small clusters, which requires compact schemes for computation. In light of this, we address an experimentally realizable four-qubit linear cluster which simulates a controlled-{\sf NOT} ({\sf CNOT}).Comment: 4 pages, 2 figures, RevTeX4; proposal for experimental setup include

Radiative decay of the X(3872) as a mixed molecule-charmonium state in QCD Sum Rules

We use QCD sum rules to calculate the width of the radiative decay of the meson X(3872), assumed to be a mixture between charmonium and exotic molecular $[c\bar{q}][q\bar{c}]$ states with $J^{PC}=1^{++}$. We find that in a small range for the values of the mixing angle, $5^0\leq\theta\leq13^0$, we get the branching ratio $\Gamma(X\to J/\psi\gamma)/\Gamma(X\to J/\psi\pi^+\pi^-)=0.19\pm0.13$, which is in agreement, with the experimental value. This result is compatible with the analysis of the mass and decay width of the mode $J/\psi(n\pi)$ performed in the same approach.Comment: 7 pages, 9 figures; revised version accepted for publication in Phys. Rev.

Butterflies of the Rocky Mountain States. Edited by Clifford D. Ferris and F. Martin Brown. University of Oklahoma Press, Norman. 464 pages, incl. 4 color plates. 1981. 35.00(cloth),35.00 (cloth), 15.95 (paper).

(excerpt) The long awaited guide to the butterflies of the Rocky Mountains will be received with great delight by many lepidopterists who collect butterflies in this rugged and beautiful region

The World of Moths. Michael Dickens and Eric Storey. Macmillan Publishing Co., Inc., New York, 1974. 128 p., 103 plates. $6.95.

(excerpt) This little book will undoubtedly please the amateur collector and rearer of the exotically and exquisitely colored species such as found in the Saturniidae and Sphing- idae. Of the 103 colored photographic plates, 69 illustrate species from these two popular families. Each species is figured on a white background in sharp and vivid color. One species is figured on a page, except for Epicopeia polydora, which includes a figure of its mimetic model Papilio rhetenor

Continuity bounds for entanglement

This note quantifies the continuity properties of entanglement: how much does entanglement vary if we change the entangled quantum state just a little? This question is studied for the pure state entanglement of a bipartite system and for the entanglement of formation of a bipartite system in a mixed state.Comment: 5 pages, submitted to Physical Review A Brief Reports. Minor typo in equation (25) corrected in resubmissio

The trumping relation and the structure of the bipartite entangled states

The majorization relation has been shown to be useful in classifying which transformations of jointly held quantum states are possible using local operations and classical communication. In some cases, a direct transformation between two states is not possible, but it becomes possible in the presence of another state (known as a catalyst); this situation is described mathematically by the trumping relation, an extension of majorization. The structure of the trumping relation is not nearly as well understood as that of majorization. We give an introduction to this subject and derive some new results. Most notably, we show that the dimension of the required catalyst is in general unbounded; there is no integer $k$ such that it suffices to consider catalysts of dimension $k$ or less in determining which states can be catalyzed into a given state. We also show that almost all bipartite entangled states are potentially useful as catalysts.Comment: 7 pages, RevTe