“…Our analysis, supported by the instanton statistics of shuttling protons, reveals that the near-room-temperature range from 250 K to 300 K is optimal for proton transfer in the protonated water hexamer.…”
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“…In this work, we use instanton theory to compute rate constants for the title reaction with and without isotopic substitutions down to temperatures of 50 K. …”
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“…Our full-dimensional ring-polymer instanton simulations show that below 100 K the concerted DHT tunneling pathway dominates but between 100 and 300 K there is a competition between concerted and stepwise pathways when nuclear quantum effects are included. …”
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“…It is responsible for the conflict between locality of the charged fields and positivity, it yields the superselection of the (unbroken) gauge charges, provides a non-perturbative explanation of the Higgs mechanism in the local gauges, implies the infraparticle structure of the charged particles in QED and the breaking of the Lorentz group in the charged sectors.A non-perturbative proof of the Higgs mechanism is discussed in the Coulomb gauge: the vector bosons corresponding to the broken generators are massive and their two point function dominates the Goldstone spectrum, thus excluding the occurrence of massless Goldstone bosons.The solution of the U(1) problem in QCD, the theta vacuum structure and the inevitable breaking of the chiral symmetry in each theta sector are derived solely from the topology of the gauge group, without relying on the semiclassical instanton approximation.…”
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“…With certain compactification where instanton effect is negligible, grand unification condition in D6-D6 intersecting-branes scenario subject to experimental constraint on proton decay provides possibility for upper limit on the string scale, $M_S$, through relationship between the string coupling, $g_s$, and the string scale. …”
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“…We briefly discuss the possibility that similar instantons in a supersymmetric version of the theory may break supersymmetry dynamically.…”
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“…This family should include $M_H$ corrected by D3-D1-D(-1)-instantons (with fivebrane corrections ignored) and, after taking a suitable rigid limit, the Coulomb branch of five-dimensional N=2 gauge theories compactified on a torus, including monopole string instantons. …”
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“…This allows to compute dyonic and stringy instantons of the gauge theory from the known results on D-instantons in string theory. …”
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“…In the Sakai-Sugimoto model of large N_c massless QCD, N baryons are described by N Yang-Mills instantons in 5 spacetime dimensions. We compute a classical short distance interaction hamiltonian for N 'tHooft instantons. …”
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“…Symmetries among the worldsheet instantons can also lead to additional selection rules for some couplings. …”
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“…Particular emphasis is put on the possibility of identifying string configurations (\lq D-instantons' and \lq D-branes') that give rise to stringy non-perturbative effects.…”
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“…We discuss higher-dimensional gravitational instantons by studying appropriate self-duality equations for the spin connection. …”
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“…We concentrate mostly on results concerning instantons and center vortices.…”
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“…A Wick rotation then yields the corresponding class of Euclidean-signature gravitational multi-instantons.…”
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“…These interactions are due to ``stringy" instantons that are associated with a space-varying coupling parameter. …”
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“…Within our context we also consider 4-dim gravitational multi-instantons.…”
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“…We then discuss non-perturbative corrections generated by asymmetric D-brane instantons. Finally we derive generating functions for MHV amplitudes at tree level in N = 5, 6 supergravities.…”
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“…Since different topological objects (instantons, vortices, monopoles, and artifacts) have different co-dimension, scaling analysis provides information on the amount of each present and their correlation with the localization of low lying eigenmodes.…”
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“…We also present some new examples of non-abelian duality for four-dimensional gravitational instantons.…”
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