Noncollinear phases in moiré magnets Hejazi, Kasra; Luo, Zhu-Xi; Balents, Leon
Proceedings of the National Academy of Sciences,
05/2020, Letnik:
117, Številka:
20
Journal Article
Recenzirano
Odprti dostop
We introduce a general framework to study moiré structures of two-dimensional Van der Waals magnets using continuum field theory. The formalism eliminates quasiperiodicity and allows a full ...understanding of magnetic structures and their excitations. In particular, we analyze in detail twisted bilayers of Néel antiferromagnets on the honeycomb lattice. A rich phase diagram with noncollinear twisted phases is obtained, and spin waves are further calculated. Direct extensions to zigzag antiferromagnets and ferromagnets are also presented. We anticipate the results and formalism demonstrated to lead to a broad range of applications to both fundamental research and experiments.
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bstract
We study the entanglement entropy in 1+1 dimensional conformal field theories in the presence of interfaces from a holographic perspective. Compared with the well-known case of boundary ...conformal field theories, interfaces allow for several interesting new observables. Depending on how the interface is located within the entangling region, the entanglement entropies differ and exhibit surprising new patterns and universal relations. While our analysis is performed within the framework of holography, we expect our results to hold more generally.
Zhu Xi Zhu, Xi; Gardner, Daniel
2022, 2022-11-08
eBook
Zhu Xi (1130-1200) was the preeminent Confucian thinker of the Song dynasty. This book presents the essential teachings of the new Confucian ("Neo-Confucian") philosophical system that he forged. ...Daniel K. Gardner's translation renders these discussions and sayings in an accessible, conversational style.
In recent years, with the continuous development of artificial intelligence (AI) technology, the digital process in chemistry has also changed with each passing day. However, the current ...digitalization of chemistry mainly uses AI technology to assist some scientific research related to computational chemistry, such as molecular design, catalyst design, reaction route design, etc. There is still no clear digital route to connect with experimental chemistry; digitization in experimental and theoretical chemistry is still in its infancy. This work sorts out some of the main references and logic of the digitalization of experimental chemistry. It puts forward a central point: in a truly digital world, there is no boundary between chemical experiments, theory, and calculation. The Mateverse platform based on Metaverse technology makes all of this possible, primarily through a digital process assisted by human researchers, which will significantly change the research paradigm of chemistry. Metaverse is a technology that should not be ignored for the future development of chemistry, which is impelled by the merged data from experiments, simulations, and theory.
Sleep deprivation (SD) is increasingly common in modern society, which can lead to the dysregulation of inflammatory responses and cognitive impairment, but the mechanisms remain unclear. Emerging ...evidence suggests that gut microbiota plays a critical role in the pathogenesis and development of inflammatory and psychiatric diseases, possibly via gut microbiota-brain interactions and neuroinflammation. The present study investigated the impact of SD on gut microbiota composition and explored whether alterations of the gut microbiota play a causal role in chronic inflammatory states and cognitive impairment that are induced by SD. We found that SD-induced gut dysbiosis, inflammatory responses, and cognitive impairment in humans. Moreover, the absence of the gut microbiota suppressed inflammatory response and cognitive impairment induced by SD in germ-free (GF) mice. Transplantation of the "SD microbiota" into GF mice activated the Toll-like receptor 4/nuclear factor-κB signaling pathway and impaired cognitive function in the recipient mice. Mice that harbored "SD microbiota" also exhibited increases in neuroinflammation and microglial activity in the hippocampus and medial prefrontal cortex. These findings indicate that gut dysbiosis contributes to both peripheral and central inflammatory processes and cognitive deficits that are induced by SD, which may open avenues for potential interventions that can relieve the detrimental consequences of sleep loss.
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bstract
In this paper we propose a Hamiltonian approach to gapped topological phases on open surfaces. Our setting is an extension of the Levin-Wen model to a 2d graph on an open surface, whose ...boundary is part of the graph. We systematically construct a series of boundary Hamiltonians such that each of them, when combined with the usual Levin-Wen bulk Hamiltonian, gives rise to a gapped energy spectrum which is topologically protected. It is shown that the corresponding wave functions are robust under changes of the underlying graph that maintain the spatial topology of the system. We derive explicit ground-state wavefunctions of the system on a disk as well as on a cylinder. For boundary quasiparticle excitations, we are able to construct their creation, annihilation, measuring and hopping operators etc. Given a bulk string-net theory, our approach provides a classification scheme of possible types of gapped boundary conditions by Frobenius algebras (modulo Morita equivalence) of the bulk fusion category; the boundary quasiparticles are characterized by bimodules of the pertinent Frobenius algebras. Our approach also offers a set of concrete tools for computations. We illustrate our approach by a few examples.
Fast pyrolysis of biomass is one of the most promising technologies for converting biomass to liquid fuels. As a result, this technology has gained extensive attention in the last two decades. The ...pyrolysis liquids, known as the bio-oils, have been regarded as promising candidates to replace petroleum fuels to be used in various thermal devices. However, bio-oils are totally different from petroleum fuels. Therefore, the successful utilization of bio-oils in terms of liquid fuels requires adequate understanding of their fuel properties. This review concentrates on the detailed fuel properties of bio-oils and discusses how these properties affect the utilization of bio-oils.
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bstract
In this paper, we use the replica approach to study the Rényi entropy
S
L
of generic locally excited states in (1+1)D CFTs, which are constructed from the insertion of multiple product of ...local primary operators on vacuum. Alternatively, one can calculate the Rényi entropy
S
R
corresponding to the same states using Schmidt decomposition and operator product expansion, which reduces the multiple product of local primary operators to linear combination of operators. The equivalence
S
L
=
S
R
translates into an identity in terms of the
F
symbols and quantum dimensions for rational CFT, and the latter can be proved algebraically. This, along with a series of papers, gives a complete picture of how the quantum information quantities and the intrinsic structure of (1+1)D CFTs are consistently related.
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bstract
We extend the holographic duality between 3d pure gravity and 2d Ising CFT proposed in ref. 1 to CFTs with boundaries. Besides the usual asymptotic boundary, the dual bulk spacetime now has ...a real cutoff, on which live branes with finite tension, giving Neumann boundary condition on the metric tensor. The strongly coupled bulk theory requires that we dress the well-known semiclassical AdS/BCFT answer with boundary gravitons, turning the partition function into the form of Virasoro characters. Using this duality, we relate the brane tensions to the modular
S
-matrix elements of the dual BCFT and derive the transformation between gravitational solutions with different brane tensions under modular
S
action.
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