Stockholm university logo, link to start page
Gå till denna sida på svenska webben

Supriya Krishnamurthy


A selection from Stockholm University publication database

  • Inferring Entropy Production from Short Experiments

    2020. Sreekanth K. Manikandan, Deepak Gupta, Supriya Krishnamurthy. Physical Review Letters 124 (12)


    We provide a strategy for the exact inference of the average as well as the fluctuations of the entropy production in nonequilibrium systems in the steady state, from the measurements of arbitrary current fluctuations. Our results are built upon the finite-time generalization of the thermodynamic uncertainty relation, and require only very short time series data from experiments. We illustrate our results with exact and numerical solutions for two colloidal heat engines.

    Read more about Inferring Entropy Production from Short Experiments
  • Efficiency Fluctuations in Microscopic Machines

    2019. Sreekanth K. Manikandan (et al.). Physical Review Letters 122 (14)


    Nanoscale machines are strongly influenced by thermal fluctuations, contrary to their macroscopic counterparts. As a consequence, even the efficiency of such microscopic machines becomes a fluctuating random variable. Using geometric properties and the fluctuation theorem for the total entropy production, a universal theory of efficiency fluctuations at long times, for machines with a finite state space, was developed by Verley et al. [Nat. Commun. 5, 4721 (2014); Phys. Rev. E 90, 052145 (2014)]. We extend this theory to machines with an arbitrary state space. Thereby, we work out more detailed prerequisites for the universal features and explain under which circumstances deviations can occur. We also illustrate our findings with exact results for two nontrivial models of colloidal engines.

    Read more about Efficiency Fluctuations in Microscopic Machines
  • Solving moment hierarchies for chemical reaction networks

    2017. Supriya Krishnamurthy, Eric Smith. Journal of Physics A 50 (42)


    The study of chemical reaction networks (CRN's) is a very active field. Earlier well-known results (Feinberg 1987 Chem. Enc. Sci. 42 2229, Anderson et al 2010 Bull. Math. Biol. 72 1947) identify a topological quantity called deficiency, for any CRN, which, when exactly equal to zero, leads to a unique factorized steady-state for these networks. No results exist however for the steady states of non-zero-deficiency networks. In this paper, we show how to write the full moment-hierarchy for any non-zero-deficiency CRN obeying mass-action kinetics, in terms of equations for the factorial moments. Using these, we can recursively predict values for lower moments from higher moments, reversing the procedure usually used to solve moment hierarchies. We show, for non-trivial examples, that in this manner we can predict any moment of interest, for CRN's with non-zero deficiency and non-factorizable steady states.

    Read more about Solving moment hierarchies for chemical reaction networks
  • Exact satisfiability threshold for k-satisfiability problems on a Bethe lattice

    2015. Supriya Krishnamurthy, Sumedha. Physical Review E. Statistical, Nonlinear, and Soft Matter Physics 92 (4)


    The satisfiability threshold for constraint satisfaction problems is that value of the ratio of constraints (or clauses) to variables, above which the probability that a random instance of the problem has a solution is zero in the large system limit. Two different approaches to obtaining this threshold have been discussed in the literature: using first or second moment methods which give rigorous bounds or using the nonrigorous but powerful replica-symmetry-breaking (RSB) approach, which gives very accurate predictions on random graphs. In this paper, we lay out a different route to obtaining this threshold on a Bethe lattice. We need make no assumptions about the solution-space structure, a key assumption in the RSB approach. Despite this, our expressions and threshold values exactly match the best predictions of the cavity method under the one-step RSB hypothesis. In addition we can use the same procedure to obtain other useful quantities on the Bethe lattice such as the second moment of the number of solutions. Our method hence provides alternate interpretations as well as motivations for the key equations in the RSB approach.

    Read more about Exact satisfiability threshold for k-satisfiability problems on a Bethe lattice
  • Nonequilibrium phase transitions in biomolecular signal transduction

    2011. Eric Smith (et al.). Physical Review E. Statistical, Nonlinear, and Soft Matter Physics 84 (5), 051917


    We study a mechanism for reliable switching in biomolecular signal-transduction cascades. Steady bistable states are created by system-size cooperative effects in populations of proteins, in spite of the fact that the phosphorylation-state transitions of any molecule, by means of which the switch is implemented, are highly stochastic. The emergence of switching is a nonequilibrium phase transition in an energetically driven, dissipative system described by a master equation. We use operator and functional integral methods from reaction-diffusion theory to solve for the phase structure, noise spectrum, and escape trajectories and first-passage times of a class of minimal models of switches, showing how all critical properties for switch behavior can be computed within a unified framework.

    Read more about Nonequilibrium phase transitions in biomolecular signal transduction

Show all publications by Supriya Krishnamurthy at Stockholm University