scholarly journals Dynamical role of Polyakov loops in the QCD thermodynamics

2016 ◽  
Vol 31 (37) ◽  
pp. 1650222 ◽  
Author(s):  
Nikita O. Agasian ◽  
Mikhail S. Lukashov ◽  
Yuri A. Simonov
Keyword(s):  
Free Energy ◽  
Trace Anomaly ◽  
Thermodynamic Potentials ◽  
Anomaly Formula ◽  
Polyakov Loops

Polyakov loops [Formula: see text], [Formula: see text] are shown to give the most important non-perturbative (np) contribution to the thermodynamic potentials. Derived from the gluonic field correlators (FCs), they enter as factors into free energy. It is shown in the SU(3) case that [Formula: see text] define to a large extent the behavior of the free energy and the trace anomaly [Formula: see text], most sensitive to np effects.

Topography of the Free Energy Landscape on the Claisen-Schmidt Condensation: Solvent and Temperature Effect in the Rate-Controlling Step

2021 ◽  
Author(s):  
Nayara Dantas Coutinho ◽  
Hugo Gontijo Machado ◽  
Valter Henrique Carvalho-Silva ◽  
Wender A. Silva
Keyword(s):  
Free Energy ◽  
Temperature Effect ◽  
Strong Influence ◽  
Aldol Condensation ◽  
Energy Landscape ◽  
Bond Formation ◽  
Free Energy Landscape ◽  
Rate Controlling Step ◽  
Formation Step

Recent studies have assigned hydroxide elimination and C=C bond formation step in base-promoted aldol condensation the role of having a strong influence in the overall rate reaction, in contrast to...

Fe–N–C Electrocatalysts in the Oxygen and Nitrogen Cycles in Alkaline Media: The Role of Iron Carbide

2021 ◽  
Author(s):  
Tomer Y. Burshtein ◽  
Denial Aias ◽  
Jin Wang ◽  
Matan Sananis ◽  
Eliyahu M. Farber ◽  
...  
Keyword(s):  
Free Energy ◽  
Energy Conversion ◽  
Oxygen Reduction ◽  
Iron Carbide ◽  
Alkaline Media ◽  
Great Promise ◽  
Nitrogen Cycles

Fe–N–C electrocatalysts hold a great promise for Pt-free energy conversion, driving the electrocatalysis of oxygen reduction and evolution, oxidation of nitrogen fuels, and reduction of N2, CO2, and NOx. Nevertheless,...

N=2 SUPERCONFORMAL INTERACTING BOSONIC MODELS

1992 ◽  
Vol 07 (04) ◽  
pp. 345-356 ◽  
Author(s):  
RON COHEN
Keyword(s):  
Free Energy ◽  
Energy Momentum Tensor ◽  
Central Charge ◽  
Oriented Graph ◽  
Momentum Tensor ◽  
Superconformal Algebra ◽  
Chiral Algebra ◽  
Bosonic Model ◽  
Coset Models

Bosonic representations of N=2 superconformal algebra are studied. We show that the free energy momentum tensor decomposes into an orthogonal sum of the interacting bosonic model (IBM) and a coset-like tensors. We define the notion of flags of models and show that the central charge does not decrease along the flags. We examine the conditions for an arbitrary un-oriented graph to form an IBM. We discuss several properties of the chiral algebra of these models and examine the role of the continuous parameters by studying an example. Finally we discuss the relations between these models and the N=2 superconformal coset models.

scholarly journals Free Energy Landscape and Rate Estimation of the Aromatic Ring Flips in Basic Pancreatic Trypsin Inhibitor Using Metadynamics

2021 ◽  
Author(s):  
Pär Söderhjelm ◽  
Mandar Kulkarni
Keyword(s):  
Free Energy ◽  
Trypsin Inhibitor ◽  
Side Chain ◽  
Side Chains ◽  
Aromatic Residues ◽  
Basic Pancreatic Trypsin Inhibitor ◽  
Pancreatic Trypsin Inhibitor ◽  
Energy Surfaces ◽  
Aromatic Side Chains

Aromatic side-chains (phenylalanine and tyrosine) of a protein flip by 180° around the Cβ-Cγ axis (χ2 dihedral of side-chain) producing two symmetry-equivalent states. The ring-flip dynamics act as an NMR probe to understand local conformational fluctuations. Ring-flips are categorized as slow (ms onwards) or fast (ns to near ms) based on timescales accessible to NMR experiments. In this study, we investigated the ability of the infrequent metadynamics approach to discriminate between slow and fast ring-flips for eight individual aromatic side-chains (F4, Y10, Y21, F22, Y23, F33, Y35, F45) of basic pancreatic trypsin inhibitor (BPTI). Well-tempered metadynamics simulations were performed to observe ring-flipping free energy surfaces for all eight aromatic residues. The results indicate that χ2 as a standalone collective variable (CV) is not sufficient to classify fast and slow ring-flips. Most of the residues needed χ1 (N−Cχα) as a complementary CV, indicating the importance of librational motions in ring-flips. Multiple pathways and mechanisms were observed for residues F4, Y10, and F22. Recrossing events are observed for residues F22 and F33, indicating a possible role of friction effects in the ring-flipping. The results demonstrate the successful application of the metadynamics based approach to estimate ring-flip rates of aromatic residues in BPTI and identify certain limitations of the approach.

Quantum Coherences as a Thermodynamic Potential

2019 ◽  
Vol 26 (04) ◽  
pp. 1950022
Author(s):  
César A. Rodríguez-Rosario ◽  
Thomas Frauenheim ◽  
Alán Aspuru-Guzik
Keyword(s):  
Entropy Production ◽  
Quantum Transport ◽  
Thermodynamic Potential ◽  
Quantum Measurements ◽  
Second Law ◽  
General Sense ◽  
Thermodynamic Potentials ◽  
General Systems ◽  
Thermodynamic Effects

Here we demonstrate how the interplay between quantum coherences and a decoherence bath, such as one given by continuos quantum measurements, lead to new kinds of thermodynamic potentials and flows. We show how a mathematical extension of thermodynamics includes decoherence baths leading to a more general sense of the zeroth and first law. We also show how decoherence adds contributions to the change in entropy production in the second law. We derive a thermodynamic potential that depends only on the interplay between quantum coherences and a decoherence thermodynamic bath. This leads to novel thermodynamic effects, such as Onsager relationships that depend on quantum coherences. This provides a thermodynamics interpretation of the role of decoherence on quantum transport in very general systems.

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