Quantum Flux and Reverse Engineering of Quantum Wavefunctions

An interpretation of the probability flux is given, based on a derivation of its eigenstates and relating them to coherent state projections on a quantum wavefunction. An extended definition of the flux operator is obtained using coherent states. We present a "processed Husimi" representation, which makes decisions using many Husimi projections at each location. The processed Husimi representation reverse engineers or deconstructs the wavefunction, yielding the underlying classical ray structure. Our approach makes possible interpreting the dynamics of systems where the probability flux is uniformly zero or strongly misleading. The new technique is demonstrated by the calculation of particle flow maps of the classical dynamics underlying a quantum wavefunction.Comment: Accepted to EP

Single spin asymmetries in inclusive hadron production from SIDIS to hadronic collisions: universality and phenomenology

In a perturbative QCD approach, with inclusion of spin and transverse momentum effects, experimental data on azimuthal asymmetries observed in polarized semi-inclusive deeply inelastic scattering and e+ e- annihilations can be used to determine the Sivers, transversity and Collins soft functions. By using these functions, within the same scheme, we predict p(transv. polarized) p -> h + X single spin asymmetries in remarkable agreement with RHIC experimental data.Comment: 5 pages, 6 ps figure

Eigenvalue distribution of the Dirac operator at finite temperature with (2+1)-flavor dynamical quarks using the HISQ action

We report on the behavior of the eigenvalue distribution of the Dirac operator in (2+1)-flavor QCD at finite temperature, using the HISQ action. We calculate the eigenvalue density at several values of the temperature close to the pseudocritical temperature. For this study we use gauge field configurations generated on lattices of size $32^3 \times 8$ with two light quark masses corresponding to pion masses of about 160 and 115 MeV. We find that the eigenvalue density below $T_c$ receives large contributions from near-zero modes which become smaller as the temperature increases or the light quark mass decreases. Moreover we find no clear evidence for a gap in the eigenvalue density up to 1.1$T_c$. We also analyze the eigenvalue density near $T_c$ where it appears to show a power-law behavior consistent with what is expected in the critical region near the second order chiral symmetry restoring phase transition in the massless limit.Comment: 7 pages, 7 figures, talk presented at the XXIX International Symposium on Lattice Field Theory, July 10-16 2011, Squaw Valley, Lake Tahoe, California, US

Scarring by homoclinic and heteroclinic orbits

In addition to the well known scarring effect of periodic orbits, we show here that homoclinic and heteroclinic orbits, which are cornerstones in the theory of classical chaos, also scar eigenfunctions of classically chaotic systems when associated closed circuits in phase space are properly quantized, thus introducing strong quantum correlations. The corresponding quantization rules are also established. This opens the door for developing computationally tractable methods to calculate eigenstates of chaotic systems.Comment: 5 pages, 4 figure

Experience with a "social model" of capacity building: the Peoples-uni

<p>Abstract</p> <p>Background</p> <p>Taking advantage of societal trends involving the "third sector", a social model of philanthropy and the open-source software and educational resource movements, provides the opportunity for online education for capacity building at low cost. The Peoples Open Access Education Initiative, Peoples-uni, aims to help build public health capacity in this way, and this paper describes its evolution.</p> <p>Methods</p> <p>The development of the Peoples-uni has involved the creation of an administrative infrastructure, calls for and identification of volunteers, development of both the information and communications technology infrastructure and course content, and identification of students and course delivery to them. A pilot course module was offered for delivery.</p> <p>Results and Discussion</p> <p>Volunteers have been prepared to become involved in the administrative structures, as trustees, members of advisory and quality assurance and educational oversight groups. More than 100 people have offered to be involved as course developers or as facilitators for course delivery, and to date 46 of these, from 13 countries, have been actively involved. Volunteer experts in information and communications technology have extended open-source course-delivery mechanisms. Following an encouraging pilot course module, 117 students from 23 countries have enrolled in the first set of six course modules. Although the business model is not fully developed, this approach allows current module delivery at USD 50 each, to be more affordable to the target audience than traditional university-based education.</p> <p>Conclusion</p> <p>A social model of capacity building in public health has been started and has been able to attract volunteers and students from a wide range of countries. The costs are likely to be low enough to allow this method to make a substantial contribution to capacity building in low-income settings.</p

The Non-Perturbative O(g6){\cal O}(g^6) Contribution to the Free Energy of Hot SU(N) Gauge Theory

The non-perturbative input necessary for the determination of the ${\cal O}(g^6)$ part of the weak coupling expansion of the free energy density for SU(2) and SU(3) gauge theories is estimated. Although the perturbative information completing the contribution to this order is missing, we give arguments that the magnetic fluctuations are dominated by screened elementary magnetic gluons.Comment: Talk presented at LATTICE96(finite temperature) 3 pages Latex2e, 3 ps figures, 14 k

Classical bifurcations and entanglement in smooth Hamiltonian system

We study entanglement in two coupled quartic oscillators. It is shown that the entanglement, as measured by the von Neumann entropy, increases with the classical chaos parameter for generic chaotic eigenstates. We consider certain isolated periodic orbits whose bifurcation sequence affects a class of quantum eigenstates, called the channel localized states. For these states, the entanglement is a local minima in the vicinity of a pitchfork bifurcation but is a local maxima near a anti-pitchfork bifurcation. We place these results in the context of the close connections that may exist between entanglement measures and conventional measures of localization that have been much studied in quantum chaos and elsewhere. We also point to an interesting near-degeneracy that arises in the spectrum of reduced density matrices of certain states as an interplay of localization and symmetry.Comment: 7 pages, 6 figure

Extracting FπF_\pi from small lattices: unquenched results

We calculate the response of the microscopic Dirac spectrum to an imaginary isospin chemical potential for QCD with two dynamical flavors in the chiral limit. This extends our previous calculation from the quenched to the unquenched theory. The resulting spectral correlation function in the $\epsilon$-regime provides here, too, a new and efficient way to measure $F_\pi$ on the lattice. We test the method in a hybrid Monte Carlo simulation of the theory with two staggered quarks.Comment: 7 pages, 5 figure