A
bstract
The concepts of operator size and computational complexity play important roles in the study of quantum chaos and holographic duality because they help characterize the structure of ...time-evolving Heisenberg operators. It is particularly important to understand how these microscopically defined measures of complexity are related to notions of complexity defined in terms of a dual holographic geometry, such as complexity-volume (CV) duality. Here we study partially entangled thermal states in the Sachdev-Ye-Kitaev (SYK) model and their dual description in terms of operators inserted in the interior of a black hole in Jackiw-Teitelboim (JT) gravity. We compare a microscopic definition of complexity in the SYK model known as K-complexity to calculations using CV duality in JT gravity and find that both quantities show an exponential-to-linear growth behavior. We also calculate the growth of operator size under time evolution and find connections between size and complexity. While the notion of operator size saturates at the scrambling time, our study suggests that complexity, which is well defined in both quantum systems and gravity theories, can serve as a useful measure of operator evolution at both early and late times.
Island in charged black holes Ling, Yi; Liu, Yuxuan; Xian, Zhuo-Yu
The journal of high energy physics,
03/2021, Volume:
2021, Issue:
3
Journal Article
Peer reviewed
Open access
A
bstract
We study the information paradox for the eternal black hole with charges on a doubly-holographic model in general dimensions, where the charged black hole on a Planck brane is coupled to ...the baths on the conformal boundaries. In the case of weak tension, the brane can be treated as a probe such that its backreaction to the bulk is negligible. We analytically calculate the entanglement entropy of the radiation and obtain the Page curve with the presence of an island on the brane. For the near-extremal black holes, the growth rate is linear in the temperature. Taking both Dvali-Gabadadze-Porrati term and nonzero tension into account, we obtain the numerical solution with backreaction in four-dimensional spacetime and find the quantum extremal surface at
t
= 0. To guarantee that a Page curve can be obtained in general cases, we propose two strategies to impose enough degrees of freedom on the brane such that the black hole information paradox can be properly described by the doubly-holographic setup.
Universal chaotic dynamics from Krylov space Erdmenger, Johanna; Jian, Shao-Kai; Xian, Zhuo-Yu
The journal of high energy physics,
08/2023, Volume:
2023, Issue:
8
Journal Article
Peer reviewed
Open access
A
bstract
Krylov complexity measures the spread of the wavefunction in the Krylov basis, which is constructed using the Hamiltonian and an initial state. We investigate the evolution of the maximally ...entangled state in the Krylov basis for both chaotic and non-chaotic systems. For this purpose, we derive an Ehrenfest theorem for the Krylov complexity, which reveals its close relation to the spectrum. Our findings suggest that neither the linear growth nor the saturation of Krylov complexity is necessarily associated with chaos. However, for chaotic systems, we observe a universal rise-slope-ramp-plateau behavior in the transition probability from the initial state to one of the Krylov basis states. Moreover, a long ramp in the transition probability is a signal for spectral rigidity, characterizing quantum chaos. Also, this ramp is directly responsible for the late-time peak of Krylov complexity observed in the literature. On the other hand, for non-chaotic systems, this long ramp is absent. Therefore, our results help to clarify which features of the wave function time evolution in Krylov space characterize chaos. We exemplify this by considering the Sachdev-Ye-Kitaev model with two-body or four-body interactions.
Chiral molecules are stereoselective with regard to specific biological functions. Enantiomers differ considerably in their physiological reactions with the human body. Safeguarding the quality and ...safety of drugs requires an efficient analytical platform by which to selectively probe chiral compounds to ensure the extraction of single enantiomers. Asymmetric synthesis is a mature approach to the production of single enantiomers; however, it is poorly suited to mass production and allows for only specific enantioselective reactions. Furthermore, it is too expensive and time-consuming for the evaluation of therapeutic drugs in the early stages of development. These limitations have prompted the development of surface-modified nanoparticles using amino acids, chiral organic ligands, or functional groups as chiral selectors applicable to a racemic mixture of chiral molecules. The fact that these combinations can be optimized in terms of sensitivity, specificity, and enantioselectivity makes them ideal for enantiomeric recognition and separation. In chiral resolution, molecules bond selectively to particle surfaces according to homochiral interactions, whereupon an enantiopure compound is extracted from the solution through a simple filtration process. In this review article, we discuss the fabrication of chiral nanoparticles and look at the ways their distinctive surface properties have been adopted in enantiomeric recognition and separation.
Hydroxylamine showed an outstanding performance on enhancing the oxidation of pollutants in Fe(II) involved advanced oxidation processes, while the detailed reaction schemes have not been fully ...revealed. Specific functions of hydroxylamine in the oxidation of benzoic acid with Fe(II)/persulfate (PDS) system were explored. With the addition of hydroxylamine, degradation kinetics of benzoic acid deviated from both two-stage kinetics and pseudo first order kinetics, but could be interpreted well with binomial regression analysis. Degradation rate constant (kobs) of benzoic acid was calculated and showed the same variation trend with hydroxylamineFe(III)2/(Fe(II)H+)2, the value of which was changed during reaction processes. A detailed kinetic model for simulating the degradation profile of benzoic acid with hydroxylamine acceleration was proposed for the first time and indicated that interactions of hydroxylamine and Fe(III) were fast equilibrium reactions, which was a dominant factor influencing the oxidation kinetics of benzoic acid in Fe(II)/hydroxylamine/PDS system. Comparative study showed that when 1.4 mM of ascorbic acid was added into Fe(II)/PDS system, degradation kinetics of benzoic acid was similar to that enhanced by hydroxylamine. However, when 0.6 mM or 1.0 mM of ascorbic acid was added, oxidation kinetics still presented as the two-stage profile. Kinetic simulations indicated that Fe(II) was produced slower from Fe(III)-ascorbic acid complexes than that with hydroxylamine, which caused the difference in oxidation kinetics. This study could improve our understanding about the effect of hydroxylamine and other reductants in promoting pollutants elimination in Fe(II)/PDS system.
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•Kinetic variations were compared in Fe(II)/persulfate system with and without hydroxylamine.•Kinetic models with fast equilibrium of hydroxylamine and Fe(III) were built to simulate degradation process.•Fast equilibrium of hydroxylamine and Fe(III) was a dominant factor for the enhanced oxidation of pollutants.
Many in vitro studies have shown that tea catechins had vevarious health beneficial effects. However, inconsistent results between in vitro and in vivo studies or between laboratory tests and ...epidemical studies are observed. Low bioavailability of tea catechins was an important factor leading to these inconsistencies. Research advances in bioavailability studies involving absorption and metabolic biotransformation of tea catechins were reviewed in the present paper. Related techniques for improving their bioavailability such as nanostructure-based drug delivery system, molecular modification, and co-administration of catechins with other bioactives were also discussed.
A
bstract
In this work, we investigate the quantum chaos in various
T
T
¯
-deformed SYK models with finite
N
, including the SYK
4
, the supersymmetric SYK
4
, and the SYK
2
models. We numerically ...study the evolution of the spectral form factor (SFF), the out-of-time ordered correlator (OTOC), and the Krylov complexity. We find that the characteristic evolution of the SFF, OTOC and K-complexity of both the SYK
4
and SSYK
4
models remains unchanged under the deformation, which implies that the properties of quantum chaos is preserved. We also identify a many-body localization behavior in the deformed SYK
2
model.
Human milk oligosaccharides (HMOS) are not digested in the proximal intestine. In distal intestine, HMOS collectively modify the microbiota, but the response of individual bacteria to individual ...components of the HMOS is not well defined. Here, each of 25 major isolates of the human intestinal microbiota was fed individual major fucosylated and sialylated HMOS in anaerobic culture. This allowed for an assessment of the influence of specific HMOS on the growth and metabolic products of individual microbiota bacteria. Most Bifidobacteria spp. and Bacteroides spp. grew, induced α-L-fucosidase activity, and produced abundant lactate or short-chain fatty acids (SCFAs) when fed 2'-fucosyllactose (2'-FL), 3-FL, and lactodifucotetraose (LDFT). Lactobacillus delbrueckii ATCC7830, Enterococcus faecalis ATCC19433, and Streptococcus thermophilus ATCC19258 exhibited slight growth, pH reduction, and lactate production when supplemented with 2'-FL or 3-FL, but not LDFT. Supplementation with 3'-sialyllactose (3'-SL) and 6'-SL promoted moderate growth of Bifidobacterium longum JCM7007, 7009, 7010, 7011, 1272, 11347, ATCC15708, Bacteroides vulgatus ATCC8482, and B. thetaiotaomicron ATCC29148; accordingly, these bacteria exhibited greater neuraminidase activity and produced copious lactate, SCFA, or both. Lactobacillus delbrueckii ATCC7830 also consumed 6'-SL. In contrast, Clostridium spp., L. rhamnosus ATCC53103, E. faecalis ATCC29200, Staphylococcus spp., Enterobacter spp., and Escherichia coli K12 did not consume milk oligosaccharides nor produce appreciable acidic fermentation products. Specific Bifidobacteria and Bacteroides differentially digest specific individual HMOS, with the major fucosylated milk oligosaccharides most strongly stimulating key species of mutualist symbionts. This suggests strategies for treating dysbiosis of the microbiota and associated inflammatory disorders.
A
bstract
We investigate the butterfly effect and charge diffusion near the quantum phase transition in holographic approach. We argue that their criticality is controlled by the holographic scaling ...geometry with deformations induced by a relevant operator at finite temperature. Specifically, in the quantum critical region controlled by a single fixed point, the butterfly velocity decreases when deviating from the critical point. While, in the non-critical region, the behavior of the butterfly velocity depends on the specific phase at low temperature. Moreover, in the holographic Berezinskii-Kosterlitz-Thouless transition, the universal behavior of the butterfly velocity is absent. Finally, the tendency of our holographic results matches with the numerical results of Bose-Hubbard model. A comparison between our result and that in the
O
(
N
) nonlinear sigma model is also given.
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