一些典型的软物质物理中的非平衡自组织现象

在软物质物理中经常有自组织(self-organization)现象发生.这一现象通常在非平衡的过程中产生,并生成非常美丽和有趣的图案与结构.具体例子包括胶体颗粒的扩散限制凝聚(diffusion limited aggregation,DLA),Hele-Shaw盒中产生的流体分形结构,凝胶的形成(gelation),生物体自组织聚集,以及颗粒类物质(granular material)运动产生的规则图案等.这些现象在软物质物理研究中产生了很多重要结果.文章以比较浅显的文字介绍这些软物质物理中的非平衡自组织现象.     

Three-dimensional nonlinear microspectroscopy and imaging of soft condensed matter

We report on the realization of a sensitive microspectroscopy and imaging approach based on a three-color femtosecond coherent anti-Stokes Raman scattering (CARS) technique with high spectral, time, and spatial resolution. Independently tunable, high-repetition rate optical parametric oscillators were used to attain a dynamic range of 5 orders of magnitude for time-domain CARS signal. The attained sensitivity permitted tracing the decay of weak and structurally complex Raman active modes in soft condensed matter. Application of this approach to imaging of the biological specimen shows a great potential in quantitative characterization of live biological media with an ability to access inter- and intra-molecular interactions.     

Experimental observation of modulation instability and optical spatial soliton arrays in soft condensed matter

In this Letter we report observations of optically induced self-organization of colloidal arrays in the presence of unpatterned counterpropagating evanescent waves. The colloidal arrays formed along the laser propagation axis are shown to be linked to the breakup of the incident field into optical spatial solitons, the lateral spacing of the arrays being related to modulation instability of the soft condensed matter system.     

Biomechanical properties of soft tissues

Viscoelasticity is the primary mechanical property of bio-soft tissues. It has been widely applied in basic research of biological tissues including cornea, lung, heart and blood vessels. Along with the development of tissue engineering research, the evaluation of soft tissue viscoelasticity is becoming more and more important. In this paper, using the Whittaker function, we give an approximate power series of the exponential integralE ₁(X) and the parametersC, ?₁ and ?₂ of the generalized relaxation functionG(t) and generalized creep functionJ(t). With expanded skin as an example, the relationship between stress relaxation, creep and stress-strain finite deformation are studied.     

Transitions to chaos in the wake of an axisymmetric bluff body

This Letter aims at understanding the dynamical process that leads to the onset of chaos in the flow past a blunt-based axisymmetric bluff body. On the basis of direct numerical simulations, conducted for Reynolds numbers ranging from 100 to 900, we show that the flow undergoes multiple transitions, successively giving rise to the SS, _RSPa${\mathrm{RSP}}_a$, _RSPb${\mathrm{RSP}}_b$, _RSPc${\mathrm{RSP}}_c$ and RSB wake states. In particular, the _RSPc${\mathrm{RSP}}_c$ state, revealed in this work via long-term computations, is characterized by intermittent vortex stretching denoting the onset of chaos before the symmetry breaking and the occurrence of the RSB state.     

Order and chaos in the interacting boson model

We investigate both quantum and classical signatures of order/chaos interplay within the symmetry triangle of the interacting boson model. Special attention is devoted to the increased regularity in the Alhassid-Whelan semiregular arc inside the symmetry triangle. Significant changes in properties of classical trajectories therein are found to accompany the strong bunching of levels in the 0⁺ spectrum. The text was submitted by the authors in English.     

Order and chaos in the geometric collective model

We investigate collective vibrations and rotations of atomic nuclei from the classical viewpoint within the geometric collective model. We quantify the proportion of regular and chaotic orbits in the phase space, observing very complex behavior of its dependence on the model control parameters, energy, and angular momentum. The text was submitted by the authors in English.     

Wetting phase transitions and critical phenomena in condensed matter

Equilibrium wetting phase transitions and critical phenomena are discussed from a phenomenological point of view. The ubiquitous character of the wetting phase transition is illustrated through its occurrence in a variety of condensed matter systems, ranging from classical fluids to superconductors and Bose-Einstein condensates. The intriguing behaviour of the three-phase contact line and its line tension, at wetting, is an example of a fundamental problem in this field on which much progress has been made.     

超快光谱技术及其在凝聚态物理研究中的应用

近年来备受关注的超快光谱技术拥有诸多特色,例如极高的时间分辨率,丰富的光与物质的非线性相互作用,可以用光子相干地调控物质的量子态,其衍生和嫁接技术带来许多凝聚态物理实验技术的变革等等.文章介绍了超快光谱技术的一般原理、时间分辨的技术实现和典型构型,并通过具体实例来展示该实验手段在凝聚态物理研究中的应用.     

Long-range power-law correlations in condensed matter physics and biophysics

We discuss the appearance of long-range power-law correlations in various systems of interest to condensed matter physicists and biophysicists, with emphasis on the recent discovery of long-range correlations in DNA sequences that contain non-coding regions.     

Torsional monopoles and torqued geometries in gravity and condensed matter

Torsional degrees of freedom play an important role in modern gravity theories as well as in condensed matter systems where they can be modeled by defects in solids. Here we isolate a class of torsion models that support torsion configurations with a localized, conserved charge that adopts integer values. The charge is topological in nature, and the torsional configurations can be thought of as torsional "monopole" solutions. We explore some of the properties of these configurations in gravity models with a nonvanishing curvature and discuss the possible existence of such monopoles in condensed matter systems. To conclude, we show how the monopoles can be thought of as a natural generalization of the Cartan spiral staircase.     

Connections between quantum chromodynamics and condensed matter physics

Features of QCD can be seen qualitatively in certain condensed matter systems. Recently some of the analyses that originated in condensed matter physics have found applications in QCD. Using examples we discuss some of the connections between the two fields and show how progress can be made by exploiting this connection. Some of the challenges that remain in the two fields are quite similar. We argue that recent algorithmic developments call for optimism in both fields.     

Mutual Chern-Simons theory and its applications in condensed matter physics

In this paper, the mutual Chern-Simons (MCS) theory is introduced as a new kind of topological gauge theory in 2+1 dimensions. We use the MCS theory in gapped phase as an effective low energy theory to describe the Z ₂ topological order of the Kitaev-Wen model. Our results show that the MCS theory can catch the key properties for the Z ₂ topological order. On the other hand, we use the MCS theory as an effective model to deal with the doped Mott insulator. Based on the phase string theory, the t-J model reduces to a MCS theory for spinons and holons. The related physics in high T _c cuprates is discussed.      

Origin of the fast magnetization relaxation at low temperatures in HTS with strong pinning

The temperature T variation of the normalized magnetization relaxation rate S in high-temperature superconductors (HTS) with strong vortex pinning exhibits a maximum in the low-T range. This was reported for various HTS, and the origin of the faster relaxation at low T appearing in standard magnetization relaxation measurements was usually related to specific pinning properties of the investigated specimens. Since the observed behaviour seems to be characteristic to all HTS with enhanced pinning (generated by random and/or correlated disorder), we show that the S(T) maximum can be explained in terms of classic collective vortex creep. The influence of thermo-magnetic instabilities in the low-T range is also evidenced. The collective (elastic) creep regime is generated by the T dependent macroscopic currents induced in the sample during standard magnetization measurements.     

Estimating perturbative coefficients in high-energy physics and condensed matter theory

Using our method to estimate perturbative coefficients in quantum field theory (QFT), we consider several examples in high-energy physics and condensed matter theory. The results, in all cases, are remarkably good for the known terms. We also predict the values of as yet unknown terms. Moreover, we consider the general convergence properties of asymptotic series in QFT.     

Ferroelectric domains and the condensed soft mode in gadolinium molybdate

Results of lattice dynamical calculations of the high temperature phase of gadolinium molybdate (GMO) support the view that the phase transition in GMO arises from a softening of a doubly degenerate zone edge mode. We find a close correlation between the displacements associated with these soft modes and the difference in the structure of the two phases, suggesting that, at the transition one or other set of soft mode displacements is ‘condensed’, or ‘frozen in’ to the structure. On this basis we can explain the ferroelectric switching.     

Quantum coherence and decoherence of protons and muons in condensed matter

The coherence in quantum superposition states of protons (and chemically similar particles, the positive muons) has been studied in some condensed matter environments. It is shown that if the proton systems and the experimental techniques used to study them are carefully selected, it is possible to observe quantum delocalization states of single particles and to understand the mechanisms for their loss of coherence. Quantum correlated two- and multiparticle states of protons lose coherence very fast when coupled to condensed matter environments, but new sub-femtosecond techniques have made them accessible to experimental studies. The degree of decoherence can be measured as function of time and the decoherence mechanisms can, at least in certain cases, be identified. Although less clean than in corresponding studies of quantum optical systems, these studies can be seen as a first step towards understanding the conditions for preservation of quantum correlation and entanglement in massive systems. Some consequences and some suggestions for future work are discussed. Received 28 August 2002 Published online 7 January 2003