Quantum anomalies and some recent developments

Some of the developments related to quantum anomalies and path integrals during the past 10 years are briefly discussed. The covered subjects include the issues related to the local counter term in the context of 2-dimensional path integral bosonization and the treatment of chiral anomaly and index theorem on the lattice. We also briefly comment on a recent analysis of the connection between the two-dimensional chiral anomalies and the four-dimensional black hole radiation.Comment: 12 pages. Invited talk given at PAQFT08, November 27-November 29, 2008, Nanyang Technological University, Singapor

A class of Heisenberg models with the orthogonal dimer ground states

Extensions of the Shastry-Sutherland model are possible in various ways. In particular, it is possible to construct a natural model in three dimensions which has the exact dimer ground state. Recently found spin gap system SrCu_2(BO_3)_2 has this structure. The exchange constants between the layers is expected to be smaller than the intra-layer couplings. However, the exactness of the dimer state for the three dimensional structure is important to understand why magnetic properties of SrCu_2(BO_3)_2 are described well by the two dimensional model.Comment: 3 pages, 5 figures, to appear in Journal of Physics: Condensed Matte

Measured Quantum Fourier Transform of 1024 Qubits on Fiber Optics

Quantum Fourier transform (QFT) is a key function to realize quantum computers. A QFT followed by measurement was demonstrated on a simple circuit based on fiber-optics. The QFT was shown to be robust against imperfections in the rotation gate. Error probability was estimated to be 0.01 per qubit, which corresponded to error-free operation on 100 qubits. The error probability can be further reduced by taking the majority of the accumulated results. The reduction of error probability resulted in a successful QFT demonstration on 1024 qubits.Comment: 15 pages, 6 figures, submitted to EQIS 2003 Special issue, Int. J. Quantum Informatio

Baryons with D5 Brane Vertex and k-Quarks

We study baryons in SU(N) gauge theories, according to the gauge/string correspondence based on IIB string theory. The D5 brane, in which $N$ fundamental strings are dissolved as a color singlet, is introduced as the baryon vertex, and its configurations are studied. We find point- and split-type of vertex. In the latter case, two cusps appears and they are connected by a flux composed of dissolved fundamental strings with a definite tension. In both cases, $N$ fundamental quarks are attached on the cusp(s) of the vertex to cancel the surface term. In the confining phase, we find that the quark in the baryon feel the potential increasing linearly with the distance from the vertex. At finite temperature and in the deconfining phase, we find a stable k-quarks "baryons", which are constructed of arbitrary number of $k(<N)$ quarks.Comment: 20 pages, 11 figure

Synchronized tapping facilitates learning sound sequences as indexed by the P300

The purpose of the present study was to determine whether and how single finger tapping in synchrony with sound sequences contributed to the auditory processing of them. The participants learned two unfamiliar sound sequences via different methods. In the tapping condition, they learned an auditory sequence while they tapped in synchrony with each sound onset. In the no tapping condition, they learned another sequence while they kept pressing a key until the sequence ended. After these learning sessions, we presented the two melodies again and recorded event-related potentials (ERPs). During the ERP recordings, 10% of the tones within each melody deviated from the original tones. An analysis of the grand average ERPs showed that deviant stimuli elicited a significant P300 in the tapping but not in the no-tapping condition. In addition, the significance of the P300 effect in the tapping condition increased as the participants showed highly synchronized tapping behavior during the learning sessions. These results indicated that single finger tapping promoted the conscious detection and evaluation of deviants within the learned sequences. The effect was related to individuals’ musical ability to coordinate their finger movements along with external auditory events

Modulation of HLA antigens in response to the binding of epidermal growth factor by A431 cells

AbstractIn a previous study [(1984) J. Cell Biol. 98, 725–731] we showed that the level of human MHC, HLA antigens on A431 carcinoma cells is reduced after these cells bind epidermal growth factor (EGF). Here we use flow cytometry to determine the effects of various doses and times of EGF treatment on HLA expression. We then show that the reduction in HLA expression is associated with a reduction in the level of phosphorylation of immunoprecipitable surface HLA antigens, although longer exposure of cells with EGF increased both surface HLA expression and their phosphorylation levels. Lateral diffusion of HLA antigens is lower in EGF-treated than in control cells. The lower diffusion coefficients measured may be causally related to the decreased phosphorylation of HLA antigens

High correlation of scotopic and photopic electroretinogram components with severity of central retinal artery occlusion

Celso S Matsumoto1,2, Kei Shinoda1, Kazuo Nakatsuka21Department of Ophthalmology, Teikyo University School of Medicine, Tokyo, Japan; 2Department of Ophthalmology, Faculty of Medicine, Oita University, Oita, JapanPurpose: The aim of this study was to determine whether a significant correlation exists between the scotopic and photopic components of electroretinograms (ERGs) and the degree of circulation disturbances caused by a central retinal artery occlusion (CRAO).Design: Observational clinical study.Participants: Sixteen patients with a CRAO (16 eyes).Methods: The circulatory disturbance in eyes with CRAO was graded as mild (group 1) when the arm-to-retina transmission time was &amp;lt;30 sec and severe (group 2) when the arm-to-retina transmission time was &amp;ge;30 sec. Scotopic and photopic ERG components in eyes with CRAO were compared with those in healthy fellow eyes with respect to the degree of circulation disturbance.Results: The scotopic and photopic b-waves were significantly reduced only in group 2, whereas the amplitudes of the photopic negative response (PhNR) of the photopic cone ERGs were significantly reduced in both groups. The amplitudes of each ERG component, except for the a-wave of the mixed rod-cone ERG, were significantly smaller in group 2 than in group 1.Conclusions: The PhNR was reduced even in group 1 with minimal circulatory disturbance and thus may be a good functional indicator.Keywords: scotopic electroretinogram, photopic electroretinogram, photopic negative response, central retinal artery occlusion, fluorescein angiograph