Author
Somendra M. Bhattacharjee
Other affiliations: Forschungszentrum Jülich, Carnegie Mellon University, Saha Institute of Nuclear Physics ...read more
Bio: Somendra M. Bhattacharjee is an academic researcher from Ashoka University. The author has contributed to research in topics: Phase transition & Renormalization group. The author has an hindex of 21, co-authored 123 publications receiving 1722 citations. Previous affiliations of Somendra M. Bhattacharjee include Forschungszentrum Jülich & Carnegie Mellon University.
Papers published on a yearly basis
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TL;DR: Various simple analytical theories for homopolymers within a unified framework using the Flory theory, and its various avatars, with the attempt at being reasonably self-contained is reviewed.
Abstract: We review various simple analytical theories for homopolymers within a unified framework. The common guideline of our approach is the Flory theory, and its various avatars, with the attempt at being reasonably self-contained. We expect this review to be useful as an introduction to the topic at the graduate student level.
142 citations
TL;DR: In this article, the authors propose a measure to quantify the nature of data collapse and extract associated exponents in problems showing self-similar or self-affine characteristics such as in equilibrium or non-equilibrium phase transitions, in critical phases, in dynamics of complex systems and many others.
Abstract: Data collapse is a way of establishing scaling and extracting associated exponents in problems showing self-similar or self-affine characteristics as, for example, in equilibrium or non-equilibrium phase transitions, in critical phases, in dynamics of complex systems and many others. We propose a measure to quantify the nature of data collapse. Via a minimization of this measure, the exponents and their error-bars can be obtained. The procedure is illustrated by considering finite-size-scaling near phase transitions and quite strikingly recovering the exact exponents.
133 citations
TL;DR: These models enable us to characterize the dynamics of the process starting from a nonequilibrium initial condition and show that the dynamical mechanism for the unzipping by force is very robust and the scaling behavior is independent of the details of the description and, hence, superuniversal.
Abstract: We report studies of the dynamics of a set of exactly solvable lattice models for the force-induced DNA unzipping transition. Besides yielding the whole equilibrium phase diagram, which reveals a reentrance, these models enable us to characterize the dynamics of the process starting from a nonequilibrium initial condition. The thermal melting of DNA displays a model dependent time evolution. On the contrary, the dynamical mechanism for the unzipping by force is very robust and the scaling behavior is independent of the details of the description and, hence, superuniversal.
128 citations
TL;DR: In this article, it is shown that double-stranded DNA can be opened by a force only if the force exceeds a critical value, and this unzipping is a critical phenomenon.
Abstract: It is shown that a double-stranded DNA can be opened by a force only if the force exceeds a critical value, and this unzipping is a critical phenomenon. From the results of an equivalent delocalization in a non-hermitian quantum mechanics problem we show the different scaling behaviours of unzipping by force and thermal melting. Based on this we make a postulate on the first step of replication of DNA.
93 citations
TL;DR: In this article, it was shown that the interfacial tension and concentration profile across the interface approach the infinite degree of polymerization limit like N−1, which is a law applicable over a limited range, and not asymptotically.
Abstract: Measurements of the interfacial tension γ between immiscible polymers of low molecular weight have not resolved the question of how γ depends on the degree of polymerization N. In this paper the issue is addressed theoretically by solving equations derived earlier, but previously solved only in the infinite molecular weight limit. The basic origin of molecular weight dependence is entropic adsorption of chain ends to the interfacial region. It is found that the interfacial tension and concentration profile across the interface approach the infinite degree of polymerization limit like N−1. No sign is found of the N−2/3 approach reported to fit the data, although not unambiguously. If correct, N−2/3 may be a law applicable over a limited range, and not asymptotically.
60 citations
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28 Jul 2005
TL;DR: PfPMP1）与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
TL;DR: In this article, a review of dissipative particle dynamics (DPD) as a mesoscopic simulation method is presented, and a link between these parameters and χ-parameters in Flory-Huggins-type models is made.
Abstract: We critically review dissipative particle dynamics (DPD) as a mesoscopic simulation method. We have established useful parameter ranges for simulations, and have made a link between these parameters and χ-parameters in Flory-Huggins-type models. This is possible because the equation of state of the DPD fluid is essentially quadratic in density. This link opens the way to do large scale simulations, effectively describing millions of atoms, by firstly performing simulations of molecular fragments retaining all atomistic details to derive χ-parameters, then secondly using these results as input to a DPD simulation to study the formation of micelles, networks, mesophases and so forth. As an example application, we have calculated the interfacial tension σ between homopolymer melts as a function of χ and N and have found a universal scaling collapse when σ/ρkBTχ0.4 is plotted against χN for N>1. We also discuss the use of DPD to simulate the dynamics of mesoscopic systems, and indicate a possible problem with...
3,837 citations
TL;DR: In this paper, a critical review of particle-hopping models of vehicular traffic is presented, focusing on the results obtained mainly from the so-called "particle hopping" models, particularly emphasizing those formulated in recent years using the language of cellular automata.
2,211 citations
TL;DR: A wide range of critical phenomena in equilibrium and growing networks including the birth of the giant connected component, percolation, $k$-core percolations, phenomena near epidemic thresholds, condensation transitions,critical phenomena in spin models placed on networks, synchronization, and self-organized criticality effects in interacting systems on networks are mentioned.
Abstract: The combination of the compactness of networks, featuring small diameters, and their complex architectures results in a variety of critical effects dramatically different from those in cooperative systems on lattices. In the last few years, important steps have been made toward understanding the qualitatively new critical phenomena in complex networks. The results, concepts, and methods of this rapidly developing field are reviewed. Two closely related classes of these critical phenomena are considered, namely, structural phase transitions in the network architectures and transitions in cooperative models on networks as substrates. Systems where a network and interacting agents on it influence each other are also discussed. A wide range of critical phenomena in equilibrium and growing networks including the birth of the giant connected component, percolation, $k$-core percolation, phenomena near epidemic thresholds, condensation transitions, critical phenomena in spin models placed on networks, synchronization, and self-organized criticality effects in interacting systems on networks are mentioned. Strong finite-size effects in these systems and open problems and perspectives are also discussed.
1,996 citations
TL;DR: In this paper, the role of pertubative renormalization group (RG) approaches and self-consistent renormalized spin fluctuation (SCR-SF) theories to understand the quantum-classical crossover in the vicinity of the quantum critical point with generalization to the Kondo effect in heavy-fermion systems is discussed.
Abstract: We give a general introduction to quantum phase transitions in strongly-correlated electron systems. These transitions which occur at zero temperature when a non-thermal parameter $g$ like pressure, chemical composition or magnetic field is tuned to a critical value are characterized by a dynamic exponent $z$ related to the energy and length scales $\Delta$ and $\xi$. Simple arguments based on an expansion to first order in the effective interaction allow to define an upper-critical dimension $D_{C}=4$ (where $D=d+z$ and $d$ is the spatial dimension) below which mean-field description is no longer valid. We emphasize the role of pertubative renormalization group (RG) approaches and self-consistent renormalized spin fluctuation (SCR-SF) theories to understand the quantum-classical crossover in the vicinity of the quantum critical point with generalization to the Kondo effect in heavy-fermion systems. Finally we quote some recent inelastic neutron scattering experiments performed on heavy-fermions which lead to unusual scaling law in $\omega /T$ for the dynamical spin susceptibility revealing critical local modes beyond the itinerant magnetism scheme and mention new attempts to describe this local quantum critical point.
1,347 citations