Phase structure of dynamical triangulation models in three dimensions

The dynamical triangulation model of three-dimensional quantum gravity is shown to have a line of transitions in an expanded phase diagram which includes a coupling μ to the order of the vertices. Monte Carlo renormalization group and finite size scaling techniques are used to locate and characterize this line. Our results indicate that for μ < μ₁ ∼ −1.0 the model is always in a crumpled phase independent of the value of the curvature coupling. For μ < 0 the results are in agreement with an approximate mean field treatment. We find evidence that this line corresponds to first-order transitions extending to positive μ. However, the behavior appears to change for μ > μ₂ ∼ 2.0−4.0. The simplest scenario that is consistent with the data is the existence of a critical end point.     

Phase transition in the scalar noise model of collective motion in three dimensions

We consider disorder-order phase transitions in the three-dimensional version of the scalar noise model (SNM) of flocking. Our results are analogous to those found for the two-dimensional case [CITE]. For small velocity (v≤0.1) a continuous, second-order phase transition is observable, with the diffusion of nearby particles being isotropic. By increasing the particle velocities the phase transition changes to first order, and the diffusion becomes anisotropic. The first-order transition in the latter case is probably caused by the interplay between anisotropic diffusion and periodic boundary conditions, leading to a boundary condition dependent symmetry breaking of the solutions.     

Diffraction in three dimensions

Atmospheric Convection . By K. A. Emanuel. 1994, £47.50 (hbk), pp. x+580. Oxford, ISBN 0 19 506630 8. Scope: text. Level: postgraduate.

Automotive Sensors . By M. H. Westbrook and J. D. Turner. 1994, £75.00, US$149.00 (hbk), pp. xviii + 253. IOP, ISBN 0 7903 0293 3. Scope: monograph. Level: specialist.

Computation in Modem Physics . By W. R. Gibbs. 1994, £38.00 (hbk), pp. xvii + 348. World Scientific, ISBN 981 02 2044 8. Scope: text. Level: undergraduate and postgraduate.

Electron Correlations in Molecules and Solids , 2nd Edn. By P. Fulde. 1993, DM78.00 (pbk), pp. xiv + 422. Springer-Verlag, ISBN 3 540 56376 8. Scope: monograph. Level: postgraduate and specialist.

Field Theory, A Path Integral Approach . By A. Das. 1994, £48.00 (hbk), pp. xv + 399. World Scientific, ISBN 981 02 1396 4. Scope: lecture notes. Level: postgraduate.

Infrared Technology Fundamentals , 2nd Edn, revised and expanded. By M. Schlessinger. 1994, US$125.00 (hbk), pp. xii + 462. Dekker, ISBN 0 8247 9259 9. Scope: monograph. Level: postgraduate and specialist.

Oceanography and Acoustics . Edited by A. R. Robinson and D. Lee. 1994, US$65.00 (hbk), pp. xvii + 257. AIP, ISBN 1 56396 203 9. Scope: multi-author review. Level: postgraduate and specialist.

Optoelectronic Integration: Physics, Technology and Applications . Edited by O. Wada. 1994, Dfl. 275.00, US$130.00, £96.25 (hbk), pp. x + 458. Kluwer, ISBN 0 7923 9453 4. Scope: multi-author review. Level: postgraduate and specialist.

Photonic Devices and Systems . Edited by R. C. Hunsperger. 1994, US$135.00 (hbk), pp. xi + 426. Dekker, ISBN 0 8247 9243 2. Scope: multi-author review. Level: postgraduate and specialist.

Physics and Our View of the World . Edited by J. Hilgevoord. 1994, US$22.95 (pbk), pp. 304. Cambridge, ISBN 0 521 47680 1. Scope: multi-author review. Level: scientists and philosophers of science.

Polymer Physics . By U.W. Gedde. 1995, £49.00 (hbk), £24.99 (pbk), pp. x + 298. Chapman &; Hall, ISBN 0 412 62640. Scope: textbook. Level: undergraduate and postgraduate.

Quantization of Gauge Systems . By M. Henneaux and C. Teitelboim. 1994, US$29.95, £25.00 (pbk) pp. xxii + 520. Princeton, ISBN 0 691 03769 8. Scope: textbook. Level: postgraduate and specialist.

Semiconductor Raman Lasers . By K. Suto and J.-I. Nlshlzawa. 1994, £63.00 (hbk), pp. ix + 226. Artech, ISBN 0 89006 667 1. Scope: monograph. Level: specialist.

Shapes and Shells in Nuclear Structure . By S. G. Nilsson and I. Ragnarsson. 1995, £60.00, US$89.95 (hbk), pp. xiv + 408. Cambridge, ISBN 0 521 37377 8. Scope: textbook. Level: postgraduate.

Supersymmetric Gauge Field Theory and String Theory . By D. Bailin and A. Love. 1994, £80.00, US$160.00 (hbk), £27.50, US$49.00 (pbk), pp. xii + 332. IOP, ISBN 0 7503 0268 2. Scope: textbook. Level: postgraduate.

Short notices Advanced Series in Neuroscience , Vol. 3. Biology and Computation, A Physicist's Choice. Reprint volume. Edited by H. Gutfreund and G. Toulouse. 1994, £94.00 (hbk) pp. xv + 852. World Scientific, ISBN 981 02 1405 7. Scope: reprints. Level: postgraduate and specialist.

Electronic Structure of Refractory Carbides and Nitrides . Edited by V. A. Gubanov, A.L. Ivanovsky and V. P. Zhukov. 1994, $79.95 (hbk) pp. xiv + 256. Cambridge University Press, ISBN 0 521 41885 2. Scope: monograph. Level: postgraduate and specialist.

Fritz London: A Scientific Biography . By K. Gavroglu. 1995, £50.00 (hbk), pp. xxiv + 299. Cambridge University Press, ISBN 0 521 43273 1. Scope: biography. Level: general reader.

Gallium Arsenide and Related Compounds 1993 . Edited by H. S. Rupprecht and G. Weinmann. 1994, £115.00, US$230.00 (hbk), pp. xxiv + 842. IOP, ISBN 0 7503 0295 X. Scope: conference proceedings. Level: postgraduate and specialist.

Matvei Petrovich Bronstein and Soviet Physics in the Thirties . By G. E. Gorelik and V. Y. Frenkel. 1994, £65.00, DM 168.00. sFr. 148.00 (hbk), pp. 208. Birkhauser, ISBN 3 7643 2752 9. Scope: biography. Level: non-specialist.

Physical Chemistry . 5th edn. By P. W. Atkins. 1994, £24.00 (pbk), pp. xix + 1145. Oxford, ISBN 0 19 855730 2. Scope textbook. Level: undergraduate.

Polyominoes. Puzzles, Patterns, Problems, and Packings . Revised and expanded 2nd edn. By S.W. Golomb. 1994, US$24.95, £19.95 (hbk) pp. xii + 181. Princeton University Press, ISBN 0 691 08573 0. Scope: text. Level: non-specialist.

Supercollider 5 . Edited by P. Hale. 1994, US$195.00 (hbk), pp. xxviii + 970. Plenum, ISBN 0 306 44705 3. Scope: conference proceedings. Level: postgraduate and specialist.

World Scientific Series in 20th Century Physics , Vol. 5. Selected Papers of Abdus Salam (With Commentary). Edited by A. Ali, C. Isham, T. Kibble and Riazuddin. 1994, £64.00 (hbk) pp. xiv + 679. World Scientific, ISBN 981 02 1662 9. Scope: reprinted papers. Level: specialist.     

Phase transitions in two dimensions

Recent developments - both theoretical and experimental - in the understanding of phase transitions in two-dimensional systems are reviewed. Topics discussed include the classification and characterization of order/disorder transitions in adsorbed monolayers, the breakdown of universality, superfluidity in helium films and the critical behaviour of the two-dimensional XY model, Abelian and non-Abelian symmetry and the analogies between the theory of phase transitions in two dimensions and quantum field theory, especially quark confinement, in four-dimensional space time.     

Dirac semimetal in three dimensions

We show that the pseudorelativistic physics of graphene near the Fermi level can be extended to three dimensional (3D) materials. Unlike in phase transitions from inversion symmetric topological to normal insulators, we show that particular space groups also allow 3D Dirac points as symmetry protected degeneracies. We provide criteria necessary to identify these groups and, as an example, present ab initio calculations of β-cristobalite BiO(2) which exhibits three Dirac points at the Fermi level. We find that β-cristobalite BiO(2) is metastable, so it can be physically realized as a 3D analog to graphene.     

Continuous freezing in three dimensions

We analyze the freezing transition in a system of hard particles with a very long-ranged repulsion. The long-range repulsion makes first-order freezing transitions continuous, but leaves the initial stages of the crystallization unchanged: the crystal phase must still nucleate. The coexistence between bulk phases is replaced by microphase separation.     

Space-filling bearings in three dimensions

We present the first space-filling bearing in three dimensions. It is shown that a packing which contains only loops of an even number of spheres can be constructed in a self-similar way and that it can act as a three-dimensional bearing in which spheres can rotate without slip and with negligible torsion friction.     

Supersymmetry breaking in three dimensions

One-loop corrections to the effective potential in three-dimensional supersymmetric massless scalar electrodynamics are calculated to see whether or not they spontaneously break supersymmetry. It is found that neither the supersymmetry nor the U(1) gauge invariance is broken by one-loop effects.     

Confined subdiffusion in three dimensions

Three-dimensional （3D） Fick＇s diffusion equation and fractional diffusion equation are solved for different reflecting boundaries. We use the continuous time random walk model （CTRW） to investigate the time-averaged mean square dis- placement （MSD） of a 3D single particle trajectory. Theoretical results show that the ensemble average of the time-averaged MSD can be expressed analytically by a Mittag-Leffler function. Our new expression is in agreement with previous formu- las in two limiting cases： （^-δ2） ~ △1 in short lag time and （^-δ2} ~ △1 -α in long lag time. We also simulate the experimental data of mRNA diffusion in living E. coli using a 3D CTRW model under confined and crowded conditions. The simulation results are well consistent with experimental results. The calculations of power spectral density （PSD） further indicate the subdiffsive behavior of an individual trajectory.     

Andreev reflection in three dimensions

正When an electron with negative charge-e is incident from a normal metal to an interface with a superconductor,it may be reflected as a hole with positive charge e at the interface.In such a way,a pair of electrons can be transferred to the superconductor and form a Cooper pair.This process of electron-hole conversion is called Andreev reflection(AR)[1].In two dimensions where the normal metal-superconductor junction is assumed to be along the x direction,     

Topological insulators in three dimensions

We study three-dimensional generalizations of the quantum spin Hall (QSH) effect. Unlike two dimensions, where a single Z2 topological invariant governs the effect, in three dimensions there are 4 invariants distinguishing 16 phases with two general classes: weak (WTI) and strong (STI) topological insulators. The WTI are like layered 2D QSH states, but are destroyed by disorder. The STI are robust and lead to novel "topological metal" surface states. We introduce a tight binding model which realizes the WTI and STI phases, and we discuss its relevance to real materials, including bismuth.     

Phase contrast MRI with improved temporal resolution by view sharing: k-space related velocity mapping properties.

Phase contrast techniques in combination with k-space segmented CINE imaging are widely used for the quantitative assessment of blood flow or tissue motion. The temporal resolution of the corresponding pulse sequences plays an important role concerning the potential of the method to fully detect time resolved flow or motion patterns. A further improvement of temporal or spatial resolution in phase contrast CINE MRI can be achieved by the application of view sharing. Based on simulations with point-spread-functions resulting from different cyclic flow or motion patterns an analysis of view sharing techniques in combination with phase contrast MRI is presented. Velocity mapping properties and the role of different k-space regions concerning the resulting values in the phase images and thus encoded velocities were investigated. It could be shown that the velocity induced phase shifts in phase contrast techniques are mainly encoded in the central sections of k-space which makes view sharing also suitable for velocity mapping. As a result the use of appropriate sampling and data acquisition schemes permits the assessment of flow or motion patterns with significantly improved temporal resolution without loss of functional information. In addition phantom measurements with an oscillation phantom were performed in order to validate the simulation results and to demonstrate the potential of view sharing techniques to accelerate phase contrast imaging and improve the detection of the underlying flow or motion dynamics.     

Mean stress effect in fatigue crack propagation

Crack propagation rates in three different grades of mild steel and two types of age hardening aluminium alloys have been measured for different stress ratios. The results show a pronounced stress ratio effect for all these materials. A model of fatigue crack propagation is formulated in terms of the size of the cyclic plastic instability zone at the crack tip rather than the zone of plastic yielding. The micro-plastic instability zone is measured by a parameter involving the ratio of the maximum stress intensity and the stress level at which macro-plastic instability occurs in the $\text{S}\text{N}$ curve of plain fatigue test pieces. Such a parameter provides a means of normalizing crack propagation results obtained for various stress ratios.