1,011 research outputs found
The curvature of the chiral pseudocritical line from LQCD: analytic continuation and Taylor expansion compared
We present a determination of the curvature of the chiral
pseudocritical line from lattice QCD at the physical point obtained
by adopting the Taylor expansion approach. Numerical simulations performed at
three lattice spacings lead to a continuum extrapolated curvature , a value that is in excellent agreement with continuum limit
estimates obtained via analytic continuation within the same discretization
scheme, . The agreement between the two calculations is a
solid consistency check for both methods.Comment: Quark Matter 201
Between Anthropology and Literature: Liminality in William Shakespeare's "Troilus and Cressida"
openA partire dalle considerazioni di Clifford Geertz sul rapporto interdipendente, bencheÌ spesso contestato, tra letteratura e antropologia, e dalle osservazioni di Victor Turner circa lâimportanza della narrazione e della performance in ambito socio-culturale, il presente elaborato si pone come obiettivo lâindagine del concetto antropologico del Limite tramite il filtro di unâopera letteraria, cercando, nelle similitudini e analogie che accomunano i due ambiti disciplinari, una comune dimensione di analisi, dibattito e riflessione. Per la sua struttura, le sue tematiche, la sua storia derivativa e la difficoltaÌ dâinquadramento in un contesto di genere, Troilus e Cressida di William Shakespeare appare come caso di studio appropriato.
Si tracceraÌ, a sostegno dellâanalisi, un excursus storico e letterario delle variazioni e reinterpretazioni della Guerra di Troia, da cui deriva il soggetto primario dellâopera. Parallelamente, si andranno a presentare gli studi di Arnold Van Gennep e Victor Turner sul concetto di limite e liminalitaÌ nel piuÌ ampio contesto culturale, evidenziando lâimportanza che essi rivestono tuttâora, in particolare nelle societaÌ a carattere urbano-industriale. Unendo dunque le osservazioni tratte in questi ambiti apparentemente divergenti e affiancandole ad un appropriato apparato critico e teorico, si cercheraÌ di dare una lettura di Troilus e Cressida, evidenziando lâemergenza del limite nelle sue macro e micro strutture narrative: dalle circostanze allâambientazione, dalla pervasiva incertezza della guerra al senso identitaria dei personaggi, dalla dissoluzione del senso dellâeroismo allâansia performativa. Oltre a offrire lâoccasione di considerare le opere letterarie come validi casi di studio etnografico, lâelaborato mira a sottolineare le potenzialitaÌ multidisciplinari dellâapproccio qui adottato, idealmente applicabili in contesti didattici per incoraggiare la ricezione critica e la rielaborazione dinamica di concetti altresiÌ consolidati. A tale scopo, il lavoro troveraÌ la sua conclusione in osservazioni personali sullâindagine, sul metodo adottato e su possibili sviluppi futuri.Drawing from Clifford Geertz's considerations on the interwoven, yet often contested relationship between literature and anthropology, ad from Victor Turner's observations regarding the importance of narration and performance in socio-cultural contexts, this paper aims to investigate the anthropological concept of Liminality through the lens of a literary work, seeking, in the shared facets of these seemingly distinct disciplines, a common ground for analysis, debate, and reflection. William Shakespeare's 'Troilus and Cressida' emerges as a fitting case study owing to its structure, thematic depth, historical derivation, and its resistance to genre classification.
The analysis will present a historical and literary survey of the variations fo the Trojan War narrative, from which derived the primary subject of the play; conversely, it will provide a theoretical framework of reference by discussing the studies on limits and liminality conducted by Arnold Van Gennep and Victor Turner, highlighting the enduring relevance of these concepts within the broader cultural landscape, particularly in modern urban-industrial societies. Combining observations drawn from these apparently disparate scope and integrating them with a robust critical and theoretical framework, the dissertation will then provide an attempt of critical and interpretative reading of Troilus and Cressida, emphasizing the emergence of the liminal element in its macro and micro narrative structures: from the circumstances of war to the setting, from the pervasive uncertainty of the conflict to the charactersâ sense of identity, from the dissolution of heroism to performative anxiety.
Beyond serving as an opportunity to consider literary works as valid cases for ethnographic inquiries, this thesis seeks to highlight the potential of the multidisciplinary approach adopted herein, which appears ideally suited for educational purposes to encourage critical reception and dynamic reinterpretations of established concepts. To this end, the work will conclude with personal observations on the investigation, the methodologies employed, and prospects for potential future developments
Solution of the Thirring model in thimble regularization
Thimble regularization of lattice field theories has been proposed as a solution to the infamous sign problem. It is conceptually very clean and powerful, but it is in practice limited by a potentially very serious issue: in general many thimbles can contribute to the computation of the functional integrals. Semiclassical arguments would suggest that the fundamental thimble could be sufficient to get the correct answer, but this hypothesis has been proven not to hold true in general. A first example of this failure has been put forward in the context of the Thirring model: the dominant thimble approximation is valid only in given regions of the parameter space of the theory. Since then a complete solution of this (simple) model in thimble regularization has been missing. In this paper we show that a full solution (taking the continuum limit) is indeed possible. It is possible thanks to a method we recently proposed which de facto evades the need to simulate on many thimbles
On the Lefschetz thimbles structure of the Thirring model
The complexification of field variables is an elegant approach to attack the
sign problem. In one approach one integrates on Lefschetz thimbles: over them,
the imaginary part of the action stays constant and can be factored out of the
integrals so that on each thimble the sign problem disappears. However, for
systems in which more than one thimble contribute one is faced with the
challenging task of collecting contributions coming from multiple thimbles. The
Thirring model is a nice playground to test multi-thimble integration
techniques; even in a low dimensional theory, the thimble structure can be
rich. It has been shown since a few years that collecting the contribution of
the dominant thimble is not enough to capture the full content of the theory.
We report preliminary results on reconstructing the complete results from
multiple thimble simulations.Comment: 7 pages, 5 figures, Proceedings of the 37th Annual International
Symposium on Lattice Field Theory, 16-22 June 2019, Wuhan, Chin
Taylor expansions and Padé approximations for Lefschetz thimbles and beyond
Deforming the domain of integration after complexification of the field variables is an intriguing idea to tackle the sign problem. In thimble regularization the domain of integration is deformed into an union of manifolds called Lefschetz thimbles. On each thimble the imaginary part of the action stays constant and the sign problem disappears. A long standing issue of this approach is how to determine the relative weight to assign to each thimble contribution in the (multi)-thimble decomposition. Yet this is an issue one has to face, as previous work has shown that different theories exist for which the contributions coming from thimbles other than the dominant one cannot be neglected. Historically, one of the first examples of such theories is the one-dimensional Thirring model. Here we discuss how Taylor expansions can be used to by-pass the need for multi-thimble simulations. If multiple, disjoint regions can be found in the parameters space of the theory where only one thimble gives a relevant contribution, multiple Taylor expansions can be carried out in those regions to reach other regions by single thimble simulations. Better yet, these Taylor expansions can be bridged by Padé interpolants. Not only does this improve the convergence properties of the series, but it also gives access to information about the analytical structure of the observables. The true singularities of the observables can be recovered. We show that this program can be applied to the one-dimensional Thirring model and to a (simple) version of HDQCD. But the general idea behind our strategy can be helpful beyond thimble regularization itself, i.e. it could be valuable in studying the singularities of QCD in the complex ”B plane. Indeed this is a program that is currently being carried out by the Bielefeld-Parma collaboration
Taylor expansions and Padé approximations for Lefschetz thimbles and beyond
Deforming the domain of integration after complexification of the field variables is an intriguing idea to tackle the sign problem. In thimble regularization the domain of integration is deformed into an union of manifolds called Lefschetz thimbles. On each thimble the imaginary part of the action stays constant and the sign problem disappears. A long standing issue of this approach is how to determine the relative weight to assign to each thimble contribution in the (multi)-thimble decomposition. Yet this is an issue one has to face, as previous work has shown that different theories exist for which the contributions coming from thimbles other than the dominant one cannot be neglected. Historically, one of the first examples of such theories is the one-dimensional Thirring model. Here we discuss how Taylor expansions can be used to by-pass the need for multi-thimble simulations. If multiple, disjoint regions can be found in the parameters space of the theory where only one thimble gives a relevant contribution, multiple Taylor expansions can be carried out in those regions to reach other regions by single thimble simulations. Better yet, these Taylor expansions can be bridged by Padé interpolants. Not only does this improve the convergence properties of the series, but it also gives access to information about the analytical structure of the observables. The true singularities of the observables can be recovered. We show that this program can be applied to the one-dimensional Thirring model and to a (simple) version of HDQCD. But the general idea behind our strategy can be helpful beyond thimble regularization itself, i.e. it could be valuable in studying the singularities of QCD in the complex ”B plane. Indeed this is a program that is currently being carried out by the Bielefeld-Parma collaboration
One-thimble regularisation of lattice field theories: is it only a dream?
Lefschetz thimbles regularisation of (lattice) field theories was put forward
as a possible solution to the sign problem. Despite elegant and conceptually
simple, it has many subtleties, a major one boiling down to a plain question:
how many thimbles should we take into account? In the original formulation, a
single thimble dominance hypothesis was put forward: in the thermodynamic
limit, universality arguments could support a scenario in which the dominant
thimble (associated to the global minimum of the action) captures the physical
content of the field theory. We know by now many counterexamples and we have
been pursuing multi-thimble simulations ourselves. Still, a single thimble
regularisation would be the real breakthrough. We report on ongoing work aiming
at a single thimble formulation of lattice field theories, in particular
putting forward the proposal of performing Taylor expansions on the dominant
thimble.Comment: 7 pages, 1 figure, Proceedings of the 37th Annual International
Symposium on Lattice Field Theory, 16-22 June 2019, Wuhan, Chin
One-thimble regularisation of lattice field theories: Is it only a dream?
Lefschetz thimbles regularisation of (lattice) field theories was put forward as a possible solution to the sign problem. Despite elegant and conceptually simple, it has many subtleties, a major one boiling down to a plain question: how many thimbles should we take into account? In the original formulation, a single thimble dominance hypothesis was put forward: in the thermodynamic limit, universality arguments could support a scenario in which the dominant thimble (associated to the global minimum of the action) captures the physical content of the field theory. We know by now many counterexamples and we have been pursuing multi-thimble simulations ourselves. Still, a single thimble regularisation would be the real breakthrough. We report on ongoing work aiming at a single thimble formulation of lattice field theories, in particular putting forward the proposal of performing Taylor expansions on the dominant thimble
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