The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Dipak Ghosh - One of the best experts on this subject based on the ideXlab platform.
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azimuthal anisotropy in high energy Nuclear Collision an approach based on complex network analysis
Advances in High Energy Physics, 2018Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:Recently, a complex network based method of visibility graph has been applied to confirm the scale-freeness and presence of fractal properties in the process of multiplicity fluctuation. Analysis of data obtained from experiments on hadron-nucleus and nucleus-nucleus interactions results in values of Power of Scale-Freeness of Visibility Graph (PSVG) parameter extracted from the visibility graphs. Here, the relativistic nucleus-nucleus interaction data have been analysed to detect azimuthal anisotropy by extending the visibility graph method and extracting the average clustering coefficient, one of the important topological parameters, from the graph. Azimuthal-distributions corresponding to different pseudorapidity regions around the central pseudorapidity value are analysed utilising the parameter. Here we attempt to correlate the conventional physical significance of this coefficient with respect to complex network systems, with some basic notions of particle production phenomenology, like clustering and correlation. Earlier methods for detecting anisotropy in azimuthal distribution were mostly based on the analysis of statistical fluctuation. In this work, we have attempted to find deterministic information on the anisotropy in azimuthal distribution by means of precise determination of topological parameter from a complex network perspective.
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a new approach of chaos and complex network method to study fluctuation and phase transition in Nuclear Collision at high energy
European Physical Journal A, 2017Co-Authors: Susmita Bhaduri, Anirban Bhaduri, Dipak GhoshAbstract:In the endeavour to study fluctuation and a signature of phase transition in ultrarelativistic Nuclear Collision during the process of particle production, an approach based on chaos and complex network is proposed. In this work we have attempted an exhaustive study of pion fluctuation in $\eta$ space, $\phi$ space, their cross-correlation and finally two-dimensional fluctuation in terms of scaling of void probability distribution. The analysis is done on the $\eta$ values and their corresponding $ \phi$ values extracted from the 32S-Ag/Br interaction at an incident energy of 200GeV per nucleon. The methods used are Multifractal Detrended Cross-Correlation Analysis (MF-DXA) and a chaos-based rigorous complex network method --Visibility Graph. The analysis reveals that the highest degree of cross-correlation between pseudorapidity and azimuthal angles exists in the most central region of the interaction. The analysis further shows that two-dimensional void distribution corresponding to the $\eta$ - $\phi$ space reveals a strong scaling behaviour. Both cross-correlation coefficients of MF-DXA and PSVG (Power of the Scale-freeness in Visibility Graph, which is implicitly connected with the Hurst exponent) can be effectively used for the quantitative assessment of pion fluctuation in a very precise manner and have the capability to assess the tendency of approaching criticality for phase transitions.
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fractal study of pion void probability distribution in ultrarelativistic Nuclear Collision and its target dependence
Modern Physics Letters A, 2016Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:There are numerous existing works on investigating the dynamics of particle production process in ultrarelativistic Nuclear Collision. In the past, fluctuation of spatial pattern has been analyzed in terms of the scaling behavior of voids. But analysis of the scaling behavior of the void in fractal scenario has not been explored yet. In this work, we have analyzed the fractality of void probability distribution with a completely different and rigorous method called visibility graph analysis, analyzing the void-data produced out of fluctuation of pions in 32S–AgBr interaction at 200 GeV in pseudo-rapidity (η) and azimuthal angle (ϕ) space. The power of scale-freeness of visibility graph denoted by PSVG is a measure of fractality, which can be used as a quantitative parameter for the assessment of the state of chaotic system. As the behavior of particle production process depends on the target excitation, we can dwell down the void probability distribution in the event-wise fluctuation resulted out of the high energy interaction for different degree of target excitation, with respect to the fractal scenario and analyze the scaling behavior of the voids. From the analysis of the PSVG parameter, we have observed that scaling behavior of void probability distribution in multipion production changes with increasing target excitation. Since visibility graph method is a classic method of complex network analysis, has been applied over fractional Brownian motion (fBm) and fractional Gaussian noises (fGn) to measure the fractality and long-range dependence of a time series successfully, we can quantitatively confirm that fractal behavior of the void probability distribution in particle production process depends on the target excitation.
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study of void probability scaling of singly charged particles produced in ultrarelativistic Nuclear Collision in fractal scenario
Advances in High Energy Physics, 2016Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:We study the fractality of void probability distribution measured in -Ag/Br interaction at an incident energy of 200 GeV per nucleon. A radically different and rigorous method called Visibility Graph analysis is used. This method is shown to reveal a strong scaling character of void probability distribution in all pseudorapidity regions. The scaling exponent, called the Power of the Scale-Freeness in Visibility Graph (PSVG), a quantitative parameter related to Hurst exponent, is strongly found to be dependent on the rapidity window size.
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study of void probability scaling of singly charged particles produced in ultrarelativistic Nuclear Collision in fractal scenario
arXiv: Data Analysis Statistics and Probability, 2016Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:In this paper, we study the fractality of void probability distribution measured in $^{32}$S-Ag/Br interaction at an incident energy of $200$ GeV per nucleon. A radically different and rigorous method called \textit{Visibility Graph} analysis is used. This method is shown to reveal a strong scaling character of void probability distribution in all pseurorapidity regions. The scaling exponent, called the Power of the Scale-freeness in Visibility Graph(PSVG), a quantitative parameter related to Hurst exponent, is strongly found to be dependent on the rapidity window size.
Susmita Bhaduri - One of the best experts on this subject based on the ideXlab platform.
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azimuthal anisotropy in high energy Nuclear Collision an approach based on complex network analysis
Advances in High Energy Physics, 2018Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:Recently, a complex network based method of visibility graph has been applied to confirm the scale-freeness and presence of fractal properties in the process of multiplicity fluctuation. Analysis of data obtained from experiments on hadron-nucleus and nucleus-nucleus interactions results in values of Power of Scale-Freeness of Visibility Graph (PSVG) parameter extracted from the visibility graphs. Here, the relativistic nucleus-nucleus interaction data have been analysed to detect azimuthal anisotropy by extending the visibility graph method and extracting the average clustering coefficient, one of the important topological parameters, from the graph. Azimuthal-distributions corresponding to different pseudorapidity regions around the central pseudorapidity value are analysed utilising the parameter. Here we attempt to correlate the conventional physical significance of this coefficient with respect to complex network systems, with some basic notions of particle production phenomenology, like clustering and correlation. Earlier methods for detecting anisotropy in azimuthal distribution were mostly based on the analysis of statistical fluctuation. In this work, we have attempted to find deterministic information on the anisotropy in azimuthal distribution by means of precise determination of topological parameter from a complex network perspective.
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a new approach of chaos and complex network method to study fluctuation and phase transition in Nuclear Collision at high energy
European Physical Journal A, 2017Co-Authors: Susmita Bhaduri, Anirban Bhaduri, Dipak GhoshAbstract:In the endeavour to study fluctuation and a signature of phase transition in ultrarelativistic Nuclear Collision during the process of particle production, an approach based on chaos and complex network is proposed. In this work we have attempted an exhaustive study of pion fluctuation in $\eta$ space, $\phi$ space, their cross-correlation and finally two-dimensional fluctuation in terms of scaling of void probability distribution. The analysis is done on the $\eta$ values and their corresponding $ \phi$ values extracted from the 32S-Ag/Br interaction at an incident energy of 200GeV per nucleon. The methods used are Multifractal Detrended Cross-Correlation Analysis (MF-DXA) and a chaos-based rigorous complex network method --Visibility Graph. The analysis reveals that the highest degree of cross-correlation between pseudorapidity and azimuthal angles exists in the most central region of the interaction. The analysis further shows that two-dimensional void distribution corresponding to the $\eta$ - $\phi$ space reveals a strong scaling behaviour. Both cross-correlation coefficients of MF-DXA and PSVG (Power of the Scale-freeness in Visibility Graph, which is implicitly connected with the Hurst exponent) can be effectively used for the quantitative assessment of pion fluctuation in a very precise manner and have the capability to assess the tendency of approaching criticality for phase transitions.
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fractal study of pion void probability distribution in ultrarelativistic Nuclear Collision and its target dependence
Modern Physics Letters A, 2016Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:There are numerous existing works on investigating the dynamics of particle production process in ultrarelativistic Nuclear Collision. In the past, fluctuation of spatial pattern has been analyzed in terms of the scaling behavior of voids. But analysis of the scaling behavior of the void in fractal scenario has not been explored yet. In this work, we have analyzed the fractality of void probability distribution with a completely different and rigorous method called visibility graph analysis, analyzing the void-data produced out of fluctuation of pions in 32S–AgBr interaction at 200 GeV in pseudo-rapidity (η) and azimuthal angle (ϕ) space. The power of scale-freeness of visibility graph denoted by PSVG is a measure of fractality, which can be used as a quantitative parameter for the assessment of the state of chaotic system. As the behavior of particle production process depends on the target excitation, we can dwell down the void probability distribution in the event-wise fluctuation resulted out of the high energy interaction for different degree of target excitation, with respect to the fractal scenario and analyze the scaling behavior of the voids. From the analysis of the PSVG parameter, we have observed that scaling behavior of void probability distribution in multipion production changes with increasing target excitation. Since visibility graph method is a classic method of complex network analysis, has been applied over fractional Brownian motion (fBm) and fractional Gaussian noises (fGn) to measure the fractality and long-range dependence of a time series successfully, we can quantitatively confirm that fractal behavior of the void probability distribution in particle production process depends on the target excitation.
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study of void probability scaling of singly charged particles produced in ultrarelativistic Nuclear Collision in fractal scenario
Advances in High Energy Physics, 2016Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:We study the fractality of void probability distribution measured in -Ag/Br interaction at an incident energy of 200 GeV per nucleon. A radically different and rigorous method called Visibility Graph analysis is used. This method is shown to reveal a strong scaling character of void probability distribution in all pseudorapidity regions. The scaling exponent, called the Power of the Scale-Freeness in Visibility Graph (PSVG), a quantitative parameter related to Hurst exponent, is strongly found to be dependent on the rapidity window size.
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study of void probability scaling of singly charged particles produced in ultrarelativistic Nuclear Collision in fractal scenario
arXiv: Data Analysis Statistics and Probability, 2016Co-Authors: Susmita Bhaduri, Dipak GhoshAbstract:In this paper, we study the fractality of void probability distribution measured in $^{32}$S-Ag/Br interaction at an incident energy of $200$ GeV per nucleon. A radically different and rigorous method called \textit{Visibility Graph} analysis is used. This method is shown to reveal a strong scaling character of void probability distribution in all pseurorapidity regions. The scaling exponent, called the Power of the Scale-freeness in Visibility Graph(PSVG), a quantitative parameter related to Hurst exponent, is strongly found to be dependent on the rapidity window size.
Argha Deb - One of the best experts on this subject based on the ideXlab platform.
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target excitation dependence of degree of multifractality and critical exponent in ultrarelativistic Nuclear Collision
Canadian Journal of Physics, 2010Co-Authors: Dipak Ghosh, Argha Deb, Ruma Saha, Rupa DasAbstract:The target excitation dependence of the degree of multifractality and critical exponent of pions produced for the 16O-AgBr interaction at 60 AGeV has been investigated. To study target excitation dependence, the data for the produced pions were distributed into three sets, depending on the number of grey tracks (ng). The different sets correspond to the different degrees of target excitation. The probability G-moments were used for the analysis in pseudorapidity space. The analysis reveals that the produced particle density distribution possesses multifractal structure for all degrees of target excitation (0 ≤ ng ≤ 3, 4 ≤ ng ≤ 7, and ng ≥ 8). The distribution Levy index and the phase transition critical exponent are calculated. The study indicates the non-thermal phase transition, but it does not show evidence for the second-order phase transition.
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levy index analysis in relativistic and ultrarelativistic Nuclear Collision evidence of non thermal phase transition
Indian Journal of Pure & Applied Physics, 2009Co-Authors: Dipak Ghosh, Argha Deb, Subrata Biswas, Pasupati Mandal, Rittika SarkarAbstract:An analysis on Levy index of compound hadrons (pions + protons) emitted from 12 C-AgBr and 24 Mg-AgBr interactions both at 4.5 AGeV/c and 32 S-AgBr interactions at 200 AGeV/c using the results of Takagi moment methodology in emission angle (cos9) space and azimuthal angle (φ) space has been presented. The results of our study reveal non-thermal phase transition at both relativistic and ultrarelativistic energy.
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ring type events and Nuclear Collision at sps energies and Nuclear refractive index
2009Co-Authors: Dipak Ghosh, Argha Deb, Prabir Kumar HaldarAbstract:In this paper we performed analyses of the data obtained of various ring-like events obtained from ultra relativistic Nuclear interactions of S–AgBr at 200 AGeV, Pb–AgBr at 158 AGeV and Au–AgBr at 11.6 AGeV in the light of Cherenkov Radiation as proposed by Dremin. The refractive index of the Nuclear medium is calculated from the knowledge of incident beam energy and cone angle of radiation. This study reveals values of the refractive index of the Nuclear medium different from values of Nuclear medium obtained for RHIC data.
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energy dependence of multidimensional fractal behavior of pions in Nuclear Collision
Fractals, 2007Co-Authors: Dipak Ghosh, Argha Deb, Rupa Das, Sitaram Pal, Jayita GhoshAbstract:This paper reports a study on multidimensional fractal behavior of pions emitted in 16O-AgBr interactions at 2.1 and 60 AGeV by dividing the full bin range into different sub-bin ranges. Analysis is performed in (Xη - Xϕ) space following two-dimensional factorial moment methodology using the concept of Hurst exponent, which takes into account the anisotropy of phase space. Different scaling behavior is observed in different bins at two different energies. The data show a positive evidence of change of fluctuation pattern from self-similarity to self-affinity with increase of energy. Multifractal dimensions have been calculated in each case and it is observed that pions at both energies exhibit multifractal behavior.
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strong self similar fluctuations of target fragments in ring like events in ultra relativistic Nuclear Collision
Chinese Physics Letters, 2006Co-Authors: Dipak Ghosh, Argha Deb, Samabrata Sarkar, Prabir Kumar HaldarAbstract:The intermittent fluctuation of target evaporated particles is studied in both ring-like and jet-like events emitted in 32S–emulsion interactions at 200 AGeV within the framework of multi-dimensional factorial moment methodology using the concept of the Hurst exponent. It is observed that the intermittent fluctuation in the ring-like event is self-similar, whereas in the jet-like event fluctuation is self-affine. However, study indicates that the strength of fluctuation in the ring-like events is much stronger than that in the jet-like events.
M K Oberthaler - One of the best experts on this subject based on the ideXlab platform.
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observation of universal dynamics in a spinor bose gas far from equilibrium
arXiv: Quantum Gases, 2018Co-Authors: Maximilian Prufer, Philipp Kunkel, Helmut Strobel, Stefan Lannig, Daniel Linnemann, Christianmarcel Schmied, Jurgen Berges, Thomas Gasenzer, M K OberthalerAbstract:The dynamics of quantum systems far from equilibrium represents one of the most challenging problems in theoretical many-body physics. While the evolution is in general intractable in all its details, relevant observables can become insensitive to microscopic system parameters and initial conditions. This is the basis of the phenomenon of universality. Far from equilibrium, universality is identified through the scaling of the spatiotemporal evolution of the system, captured by universal exponents and functions. Theoretically, this has been studied in examples as different as the reheating process in inflationary universe cosmology, the dynamics of Nuclear Collision experiments described by quantum chromodynamics, or the post-quench dynamics in dilute quantum gases in non-relativistic quantum field theory. Here we observe the emergence of universal dynamics by evaluating spatially resolved spin correlations in a quasi one-dimensional spinor Bose-Einstein condensate. For long evolution times we extract the scaling properties from the spatial correlations of the spin excitations. From this we find the dynamics to be governed by transport of an emergent conserved quantity towards low momentum scales. Our results establish an important class of non-stationary systems whose dynamics is encoded in time independent scaling exponents and functions signaling the existence of non-thermal fixed points. We confirm that the non-thermal scaling phenomenon involves no fine-tuning, by preparing different initial conditions and observing the same scaling behaviour. Our analog quantum simulation approach provides the basis to reveal the underlying mechanisms and characteristics of non-thermal universality classes. One may use this universality to learn, from experiments with ultra-cold gases, about fundamental aspects of dynamics studied in cosmology and quantum chromodynamics.
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observation of universal dynamics in a spinor bose gas far from equilibrium
Nature, 2018Co-Authors: Maximilian Prufer, Philipp Kunkel, Helmut Strobel, Stefan Lannig, Daniel Linnemann, Christianmarcel Schmied, Jurgen Berges, Thomas Gasenzer, M K OberthalerAbstract:Predicting the dynamics of quantum systems far from equilibrium represents one of the most challenging problems in theoretical many-body physics1,2. While the evolution of a many-body system is in general intractable in all its details, relevant observables can become insensitive to microscopic system parameters and initial conditions. This is the basis of the phenomenon of universality. Far from equilibrium, universality is identified through the scaling of the spatio-temporal evolution of the system, captured by universal exponents and functions. Theoretically, this has been studied in examples as different as the reheating process in inflationary Universe cosmology3,4, the dynamics of Nuclear Collision experiments described by quantum chromodynamics5,6, and the post-quench dynamics in dilute quantum gases in non-relativistic quantum field theory7–11. However, an experimental demonstration of such scaling evolution in space and time in a quantum many-body system has been lacking. Here we observe the emergence of universal dynamics by evaluating spatially resolved spin correlations in a quasi-one-dimensional spinor Bose–Einstein condensate12–16. For long evolution times we extract the scaling properties from the spatial correlations of the spin excitations. From this we find the dynamics to be governed by an emergent conserved quantity and the transport of spin excitations towards low momentum scales. Our results establish an important class of non-stationary systems whose dynamics is encoded in time-independent scaling exponents and functions, signalling the existence of non-thermal fixed points10,17,18. We confirm that the non-thermal scaling phenomenon involves no fine-tuning of parameters, by preparing different initial conditions and observing the same scaling behaviour. Our analogue quantum simulation approach provides the basis with which to reveal the underlying mechanisms and characteristics of non-thermal universality classes. One may use this universality to learn, from experiments with ultracold gases, about fundamental aspects of dynamics studied in cosmology and quantum chromodynamics.
Maximilian Prufer - One of the best experts on this subject based on the ideXlab platform.
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observation of universal dynamics in a spinor bose gas far from equilibrium
arXiv: Quantum Gases, 2018Co-Authors: Maximilian Prufer, Philipp Kunkel, Helmut Strobel, Stefan Lannig, Daniel Linnemann, Christianmarcel Schmied, Jurgen Berges, Thomas Gasenzer, M K OberthalerAbstract:The dynamics of quantum systems far from equilibrium represents one of the most challenging problems in theoretical many-body physics. While the evolution is in general intractable in all its details, relevant observables can become insensitive to microscopic system parameters and initial conditions. This is the basis of the phenomenon of universality. Far from equilibrium, universality is identified through the scaling of the spatiotemporal evolution of the system, captured by universal exponents and functions. Theoretically, this has been studied in examples as different as the reheating process in inflationary universe cosmology, the dynamics of Nuclear Collision experiments described by quantum chromodynamics, or the post-quench dynamics in dilute quantum gases in non-relativistic quantum field theory. Here we observe the emergence of universal dynamics by evaluating spatially resolved spin correlations in a quasi one-dimensional spinor Bose-Einstein condensate. For long evolution times we extract the scaling properties from the spatial correlations of the spin excitations. From this we find the dynamics to be governed by transport of an emergent conserved quantity towards low momentum scales. Our results establish an important class of non-stationary systems whose dynamics is encoded in time independent scaling exponents and functions signaling the existence of non-thermal fixed points. We confirm that the non-thermal scaling phenomenon involves no fine-tuning, by preparing different initial conditions and observing the same scaling behaviour. Our analog quantum simulation approach provides the basis to reveal the underlying mechanisms and characteristics of non-thermal universality classes. One may use this universality to learn, from experiments with ultra-cold gases, about fundamental aspects of dynamics studied in cosmology and quantum chromodynamics.
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observation of universal dynamics in a spinor bose gas far from equilibrium
Nature, 2018Co-Authors: Maximilian Prufer, Philipp Kunkel, Helmut Strobel, Stefan Lannig, Daniel Linnemann, Christianmarcel Schmied, Jurgen Berges, Thomas Gasenzer, M K OberthalerAbstract:Predicting the dynamics of quantum systems far from equilibrium represents one of the most challenging problems in theoretical many-body physics1,2. While the evolution of a many-body system is in general intractable in all its details, relevant observables can become insensitive to microscopic system parameters and initial conditions. This is the basis of the phenomenon of universality. Far from equilibrium, universality is identified through the scaling of the spatio-temporal evolution of the system, captured by universal exponents and functions. Theoretically, this has been studied in examples as different as the reheating process in inflationary Universe cosmology3,4, the dynamics of Nuclear Collision experiments described by quantum chromodynamics5,6, and the post-quench dynamics in dilute quantum gases in non-relativistic quantum field theory7–11. However, an experimental demonstration of such scaling evolution in space and time in a quantum many-body system has been lacking. Here we observe the emergence of universal dynamics by evaluating spatially resolved spin correlations in a quasi-one-dimensional spinor Bose–Einstein condensate12–16. For long evolution times we extract the scaling properties from the spatial correlations of the spin excitations. From this we find the dynamics to be governed by an emergent conserved quantity and the transport of spin excitations towards low momentum scales. Our results establish an important class of non-stationary systems whose dynamics is encoded in time-independent scaling exponents and functions, signalling the existence of non-thermal fixed points10,17,18. We confirm that the non-thermal scaling phenomenon involves no fine-tuning of parameters, by preparing different initial conditions and observing the same scaling behaviour. Our analogue quantum simulation approach provides the basis with which to reveal the underlying mechanisms and characteristics of non-thermal universality classes. One may use this universality to learn, from experiments with ultracold gases, about fundamental aspects of dynamics studied in cosmology and quantum chromodynamics.
