We formulate the problem of optimizing the sampling of natural images using an array of linear filters. Optimization of information capacity is constrained by the noise levels of the individual channels and by a penalty for the...
moreWe formulate the problem of optimizing the sampling of natural images using an array of linear filters. Optimization of information capacity is constrained by the noise levels of the individual channels and by a penalty for the construction of long-range interconnections in the array. At low signal-to-noise ratios the optimal filter characteristics correspond to bound states of a Schrodinger equation in which the signal spectrum plays the role of the potential. The resulting optimal filters are remarkably similar to those observed in the mammalian visual cortex and the retinal ganglion cells of lower vertebrates. The observed scale invariance of natural images plays an essential role in this construction.
We study localization and delocalization in a class of non-Hermitian Hamiltonians inspired by the problem of vortex pinning in superconductors. In various simplified models we are able to obtain analytic descriptions, in particular, of...
moreWe study localization and delocalization in a class of non-Hermitian Hamiltonians inspired by the problem of vortex pinning in superconductors. In various simplified models we are able to obtain analytic descriptions, in particular, of the nonperturbative emergence of a forked structure (the appearance of "wings") in the density of states. We calculate how the localization length diverges at the localization-delocalization transition. We map some versions of this problem onto a random walker problem in two dimensions. For a certain model, we find an intricate structure in its density of states.
A. Zee Institute for Theoretical Physics,Uniuersity ofCalifornia, Santa Barbara, California 93106 4030-{Received 11May 1992) We study interlayer tunneling in some double-layered quantum Hall states that contain a neutral gap-less...
moreA. Zee Institute for Theoretical Physics,Uniuersity ofCalifornia, Santa Barbara, California 93106 4030-{Received 11May 1992) We study interlayer tunneling in some double-layered quantum Hall states that contain a neutral gap-less superOuid mode. A tunneling current less than ...
In multi-layer printed circuit board (PCB) manufacturing, adhesion promoters are applied between the inner layer copper surface and prepreg resin to ensure superior bonding reliability. Traditional adhesion promoters used over the last...
moreIn multi-layer printed circuit board (PCB) manufacturing, adhesion promoters are applied between the inner layer copper surface and prepreg resin to ensure superior bonding reliability. Traditional adhesion promoters used over the last decade include processes such as black oxide and oxide replacement processes. Both inner layer bonding enhancement processes apply a coating or chemically etch the copper surface to create certain amount of roughness and provide mechanical bonding. Most oxide replacement processes also cover the roughened surface with organic coatings that further improves the inner layer adhesion through chemical bonding as well. While the conventional inner layer adhesion promoters pose no major functionality issues to the manufacturing of commodity PCBs, the impact on the electrical performance for high frequency application is a concern. Over the past decade, the remarkable advances in the mobile phone industry and wireless networks have pushed the high frequency industry to uncharted territories. With the emergence of 3G cellular network in China, the demand for high frequency multilayer boards will continue to increase. As the amount of data transfer increases, the signal frequency also increases accordingly. It is also known that as operating frequency approach 1 GHz, electrical signals no longer pass through the bulk of the copper track but instead travel through the skin that closely follows the track contour. As the "skin effect" phenomenon is observed, any small changes in surface area or roughness can result in significant impact on the impedance and consequently in signal loss. By maintaining a smooth and consistent track surface, non-etching adhesion promoter type processes can adhere to a more stringent track impedance requirement and provide a reduced signal loss at higher operating frequencies. This paper discusses a number of simulation and modeling investigations in which the effect of a non-etching adhesion promoter is directly com- pared with an etch-based process. The paper explores specifically the influence of surface roughness on the high frequency signal loss characteristics of a variety of track geometries. The study clearly shows clear advantages of non-etching bonding technologies over the conventional surface roughening process when operating at higher frequencies.
... PHY87-06501 at the University of Utah. References [ 1 ] S. Deser, R. Jackiw and S. Templeton Phys. Rev. Lett. 48 (1982) 975; Ann. Phys. ... [ 8 ] YS Wu and A. Zee, Phys. Lett. B 147 (1984) 325. [9]AM Din and WJ Zakrewski, Phys. Lett....
more... PHY87-06501 at the University of Utah. References [ 1 ] S. Deser, R. Jackiw and S. Templeton Phys. Rev. Lett. 48 (1982) 975; Ann. Phys. ... [ 8 ] YS Wu and A. Zee, Phys. Lett. B 147 (1984) 325. [9]AM Din and WJ Zakrewski, Phys. Lett. B 146 (1984) 341. 10 ] T. Jarosewicz, Phys. ...
We discuss some new quantum numbers (spin vector) for the Hall fluid, representing orbital spin degrees of freedom. We show that the spin vectors are quantized. In the absence of impurites, two Hall fluids with different spin vectors...
moreWe discuss some new quantum numbers (spin vector) for the Hall fluid, representing orbital spin degrees of freedom. We show that the spin vectors are quantized. In the absence of impurites, two Hall fluids with different spin vectors cannot change into each other without a phase transition and closing of the energy gap. In principle the spin vector can be
... B5, 411 (1968). i3W. P. Hesse et al., Phys. Rev. Lett. 25, 613 (1970), and references therein. 14V. Barger and RJN Phillips, Phys. Rev. 187, 2210 (1969). 15G. V. Dass, C. Michael, and RJNPhillips, Nucl. Phys. B9, 549 (1969). 16V....
more... B5, 411 (1968). i3W. P. Hesse et al., Phys. Rev. Lett. 25, 613 (1970), and references therein. 14V. Barger and RJN Phillips, Phys. Rev. 187, 2210 (1969). 15G. V. Dass, C. Michael, and RJNPhillips, Nucl. Phys. B9, 549 (1969). 16V. Barger and RJN Phillips, Phys. Rev. Lett. ...
We describe in the Heisenberg anti-ferromagnet in two and three dimensional spaces non-Abelian flux states about which the low energy excitations obey the Dirac equation. A gap in the energy spectrum may be opened. These states describe...
moreWe describe in the Heisenberg anti-ferromagnet in two and three dimensional spaces non-Abelian flux states about which the low energy excitations obey the Dirac equation. A gap in the energy spectrum may be opened. These states describe spin liquids.
I discuss various thoughts, old and new, about the cosmological constant (or dark energy) paradox. In particular, I suggest the possibility that the cosmological "constant" may decay as [Formula: see text], where τ is the age of...
moreI discuss various thoughts, old and new, about the cosmological constant (or dark energy) paradox. In particular, I suggest the possibility that the cosmological "constant" may decay as [Formula: see text], where τ is the age of the universe.
... A generalization of Wilson's loop prescription to include spin is proposed. Instantons are shown to generate a spin-spin interaction between quarks. ... Thus, we expect a term in the spin-spininteraction...
more... A generalization of Wilson's loop prescription to include spin is proposed. Instantons are shown to generate a spin-spin interaction between quarks. ... Thus, we expect a term in the spin-spininteraction independent of the separation R between the quark and the antiquark [Fig. ...
In studying the ability of feed forward networks to perform perceptual tasks, we train a network to master a specific task, that of deciding whether a given object is to the left or to the right of another object. We discuss in general...
moreIn studying the ability of feed forward networks to perform perceptual tasks, we train a network to master a specific task, that of deciding whether a given object is to the left or to the right of another object. We discuss in general terms such issues as architecture, drilling, generalization, abstraction, learning from small examples, and versatility.
... B5, 411 (1968). i3W. P. Hesse et al., Phys. Rev. Lett. 25, 613 (1970), and references therein. 14V. Barger and RJN Phillips, Phys. Rev. 187, 2210 (1969). 15G. V. Dass, C. Michael, and RJNPhillips, Nucl. Phys. B9, 549 (1969). 16V....
more... B5, 411 (1968). i3W. P. Hesse et al., Phys. Rev. Lett. 25, 613 (1970), and references therein. 14V. Barger and RJN Phillips, Phys. Rev. 187, 2210 (1969). 15G. V. Dass, C. Michael, and RJNPhillips, Nucl. Phys. B9, 549 (1969). 16V. Barger and RJN Phillips, Phys. Rev. Lett. ...
Linking Numbers, Spin, and Statistics of Solitons. Frank Wilczek Institute forTheoretical Physics, University of California, Santa Barbara, California 93106. A. Zee * Institute for Theoretical Physics, University of California, Santa ...
... term remains an unsolved difficulty [8] * s .) We recall that the WeylEddington action is ex ... dynamically induced EinsteinHilbert term could provide an attractive renormalizable description of gravity which reduces ... In spectral...
more... term remains an unsolved difficulty [8] * s .) We recall that the WeylEddington action is ex ... dynamically induced EinsteinHilbert term could provide an attractive renormalizable description of gravity which reduces ... In spectral function language p is given by din2 o(m2) p= , where o ...
... masses'2 of a few MeV. (vii) Another way of looking at the effect above is to note that the axial-vector part of the neutral current looks like (schematically) iuu-3dd+(c-Css+ tt-bb)+ - . (2.4) In most...
more... masses'2 of a few MeV. (vii) Another way of looking at the effect above is to note that the axial-vector part of the neutral current looks like (schematically) iuu-3dd+(c-Css+ tt-bb)+ - . (2.4) In most phenomenological analyses one ...