470 research outputs found

    Out-of-Time-Ordered Correlators in (T2)n/Zn(T^2)^n/\mathbb{Z}_n

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    In this note we continue analysing the non-equilibrium dynamics in the (T2)n/Zn(T^2)^n/\mathbb{Z}_n orbifold conformal field theory. We compute the out-of-time-ordered four-point correlators with twist operators. For rational η (=p/q)\eta \ (=p/q) which is the square of the compactification radius, we find that the correlators approach non-trivial constants at late time. For n=2n=2 they are expressed in terms of the modular matrices and for higher nn orbifolds are functions of pqpq and nn. For irrational η\eta, we find a new polynomial decay of the correlators that is a signature of an intermediate regime between rational and chaotic models.Comment: 20 pages, 3 figure

    Semiclassical analysis of the bifundamental QCD on R2×T2\mathbb{R}^2\times T^2 with 't Hooft flux

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    We study the phase structure of bifundamental quantum chromodynamics (QCD(BF)), which is the 44-dimensional SU(N)×SU(N)SU(N) \times SU(N) gauge theory coupled with the bifundamental fermion. Firstly, we refine constraints on its phase diagram from 't Hooft anomalies and global inconsistencies, and we find more severe constraints than those in previous literature about QCD(BF). Secondly, we employ the recently-proposed semiclassical approach for confining vacua to investigate this model concretely, and this is made possible via anomaly-preserving T2T^2 compactification. For sufficiently small T2T^2 with the 't Hooft flux, the dilute gas approximation of center vortices gives reliable semiclassical computations, and we determine the phase diagram as a function of the fermion mass mm, two strong scales Λ1,Λ2\Lambda_{1},\Lambda_2, and two vacuum angles, θ1,θ2\theta_1, \theta_2. In particular, we find that the QCD(BF) vacuum respects the Z2\mathbb{Z}_2 exchange symmetry of two gauge groups. Under the assumption of the adiabatic continuity, our result successfully explains one of the conjectured phase diagrams in the previous literature and also gives positive support for the nonperturbative validity of the large-NN orbifold equivalence between QCD(BF) and N=1\mathcal{N}=1 SU(2N)SU(2N) supersymmetric Yang-Mills theory. We also comment on problems of domain walls.Comment: 33 pages, 5 figures, small discussion adde

    Degradable and Nanosegregated Elastomers with Multiblock Sequences of Biobased Aromatic Mesogens and Biofunctional Aliphatic Oligocarbonates

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    We have developed multiblock aromatic/aliphatic condensation polymers, comprising side-chain biofunctionalized aliphatic oligocarbonates and biobased aromatic ester triad mesogens up to 17 wt %. Nanosegregation of the aromatic mesogen-rich domains with diameters of approximately 10 nm from the soft aliphatic polymer matrix is suggested by atomic force microscopy. The polymers exhibit rubberlike properties, unlike the corresponding aliphatic polycarbonate forming viscous liquid. These properties support the interchain interactions between the aromatic mesogens, which can serve as physical cross-linking. The aromatic ester triad mesogens in the multiblock polymers significantly bolster the tolerance to organocatalytic hydrolysis and methanolysis of the polymer chains but are eventually degraded. The multiblock polymers show degradation behavior slightly faster than poly(L-lactide), whereas poly(ethylene terephthalate) remains intact under the same condition. The present study demonstrates the efficacy of aromatic ester triad mesogens incorporated into the sequences of biodegradable aliphatic polycarbonates to enhance their physical properties while retaining degradability

    Mechanism of Nucleation Pathway Selection in Binary Lennard-Jones Solution: A Combined Study of Molecular Dynamics Simulation and Free Energy Analysis

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    The nucleation process, which is the initial step in particle synthesis, determines the properties of the resultant particles. Although recent studies have observed various nucleation pathways, the physical factors that determine these pathways have not been fully elucidated. Herein, we conducted molecular dynamics simulations in a binary Lennard-Jones system as a model solution and found that the nucleation pathway can be classified into four types depending on microscopic interactions. The key parameters are (1) the strength of the solute–solute interaction and (2) the difference between the strengths of the like-pair and unlike-pair interactions. The increment of the former alters the nucleation mechanism from a two-step to a one-step pathway, whereas that of the latter causes quick assembly of solutes. Moreover, we developed a thermodynamic model based on the formation of core-shell nuclei to calculate the free energy landscapes. Our model successfully described the pathway observed in the simulations and demonstrated that the two parameters, (1) and (2), define the degree of supercooling and supersaturation, respectively. Thus, our model interpreted the microscopic insights from a macroscopic point of view. Because the only inputs required for our model are the interaction parameters, our model can a priori predict the nucleation pathway
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