1824 June 2017
Palacio de Congresos
Europe/Madrid timezone
Theoretical Developments
Place
Location: Palacio de Congresos
Address: PALACIO DE CONGRESOS
Paseo del Violón s/n, 18006
Granada, SPAIN
Date:
from 21 Jun 09:00 to 23 Jun 19:10
Conveners

21 Jun 09:00  11:00
 catterall, simon (syracuse university)

21 Jun 11:30  13:30
 Prof. Chandrasekharan, Shailesh (Duke University)

22 Jun 15:00  16:40
 Dr. Dalla Brida, Mattia (Universita' di MilanoBicocca & INFN)

22 Jun 17:10  19:10
 Prof. Onogi, Tetsuya (Osaka University)

23 Jun 15:00  16:40
 Prof. Gattringer, Christof (University of Graz, Austria)

23 Jun 17:10  19:10
 Dr. CIchy, Krzysztof (Goethe University Frankfurt)
Timetable  Contribution List
Displaying 34
contributions
out of
34
The gradient flow and its small flowtime expansion provide a very versatile method to represent renormalized composite operators in a regularizationindependent manner. This technique has been utilized to construct typical Noether currents such as the energymomentum tensor and the axialvector current in lattice gauge theory. In this paper, we apply the same technique to the supercurrent in the
... More
Presented by Ms. Aya KASAI
on
21/6/2017
at
10:00
The Abelian Color Cycle (ACC) technique is a method to dualize nonabelian lattice field theories.
The crucial step of this approach is to decompose the action into a sum over complex numbers by writing explicitly all the traces, matrix and vector multiplications. This allows for the factorization of the Boltzmann weight into local factors, that are then Taylor expanded. After the analytical inte
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Presented by Ms. Carlotta MARCHIS
on
21/6/2017
at
11:50
This is the second talk followed to the first one of general formulation
proposing a new type of lattice field theory without lattice
chiral fermion problem. It has been formulated by the momentum space by
introducing a new continuum momentum on the lattice and has nonlocal
nature in the coordinate space. The recovery of associativity of the nonlocal
product led us to this new formulat
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Presented by Prof. Noboru KAWAMOTO
on
21/6/2017
at
8:40
We propose an unconventional formulation of lattice field theories which is quite general, although originally motivated by the quest of exact lattice supersymmetry.
Two long standing problems have a solution in this context:
1) Each degree of freedom on the lattice corresponds to 2^d degrees of freedom in the continuum, but all these doublers have(in the case of fermions) the same chirality and
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Presented by Mr. Alessandro D'ADDA, Prof. Noboru KAWAMOTO
on
21/6/2017
at
8:20
We study a tensor network formulation of the two dimensional lattice $\mathcal{N}=1$ Wess$\unicode{x2013}$Zumino model with Wilson derivatives for fermions and bosons. The tensor renormalization group allows us to compute the partition function without the sign problem, and basic ideas to obtain a tensor network for both fermion and scalar boson systems were already given in previous works. While
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Presented by Mr. Ryo SAKAI
on
23/6/2017
at
18:10
Recently, the AtiyahPatodiSinger(APS) index theorem attracts attention for understanding physics on the surface of materials in topological phases. Although it is widely applied to physics, the mathematical setup in original APS index theorem is too abstract and general (allowing nontrivial metric and so on) and also the connection bewteen the APS boundary condition and the physical boundary co
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Presented by Prof. Tetsuya ONOGI
on
23/6/2017
at
15:40
The positivity of the Boltzmann weight, needed for its probabilistic interpretation and for the application of the Monte Carlo method is absent for theories with complex actions. We propose avoiding the latter problem substituting Monte Carlo simulations by computations with convergent 'nonperturbative' expansions. We discuss constructions of such expansions and first numerical results on the exa
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Presented by Dr. Vasily SAZONOV
on
22/6/2017
at
18:10
We have developed Grassmann higher order tensor renormalization group (GHOTRG) to analyze higher dimensional fermionic systems. We first apply it to threedimensional free Wilson fermions as a benchmark to check its effectiveness. The results of the free energy and the fermion Green functions are presented in comparison with the exact values. We also briefly discuss to what extent the results are
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Presented by Mr. Yusuke YOSHIMURA
on
21/6/2017
at
12:50
Various approaches to construction of dual formulations of non abelian lattice gauge theories are reviewed. In the case of U(N) LGT we use a theory of the Weingarten functions to construct a dual formulation. In particular, the dual representations are constructed 1) for pure gauge models in all dimensions, 2) in the strong coupling limit for the models with arbitrary number of flavours and 3) for
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Presented by Dr. Oleg BORISENKO
on
21/6/2017
at
13:10
Flavortwisted boundary conditions can be used for exponential reduction of finite volume artifacts in flavoraveraged observables in lattice QCD calculations with SU(Nf) light quark flavor symmetry. Finite volume artifact reduction arises from destructive interference effects in a manner closely related to the phase averaging which leads to large Nc volume independence. With a particular choice o
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Presented by Mr. Aleksey CHERMAN
on
22/6/2017
at
15:00
The threeparticle quantization condition is derived, using the particledimer picture in the nonrelativistic effective field theory. The procedure for the extraction of various observables in the threeparticle sector (the particledimer scattering amplitudes, breakup amplitudes, etc.) from the finitevolume lattice spectrum is discussed in detail. As an illustration of the general formalism, th
... More
Presented by Dr. Akaki RUSETSKY
on
22/6/2017
at
16:00
We argue that it is possible to uniquely define function support that preserves elementary properties of the function domain. This leads, among other things, to rigorous and general definition of the localization property.
Presented by Prof. Ivan HORVATH
on
22/6/2017
at
18:50
Using the example of a two dimensional fourfermion lattice field theory, we show that Feynman diagrams
can generate a mass gap in a theory with massless fermions that interact via a marginally relevant coupling.
We show this by introducing an infrared cutoff that makes the perturbation series for the partition function convergent. One can then use a Monte Carlo approach to sample sufficiently h
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Presented by Prof. Shailesh CHANDRASEKHARAN
on
23/6/2017
at
15:20
We investigate the possibility of using numerical stochastic perturbation theory (NSPT) to probe high orders in the perturbative expansion of lattice gauge theories with massless Wilson fermions. Twisted boundary conditions are used to regularise the gauge zeromode; the extension of these boundary conditions to include fermions in the fundamental representation requires to introduce a smell degre
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Presented by Mr. Gianluca FILACI
on
22/6/2017
at
15:40
Through the development of manybody methodology and algorithms, it has become possible to describe quantum systems composed of a large number of particles with great accuracy. Essential to all these methods is the application of auxiliary fields via the HubbardStratonovich transformation. This transformation effectively reduces twobody interactions to interactions of one particle with the auxil
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Presented by Mr. Christopher KOERBER
on
22/6/2017
at
16:20
We derive a full KramersWannier dualization of the SU(2) principal chiral model. In a first step the trace and color multiplications in the action are written explicitly, such that only commuting numbers ("Abelian Color Fluxes") remain. The individual Boltzmann factors are then expanded and the original degrees of freedom are integrated out explicitly. The expansion indices become the new variabl
... More
Presented by Prof. Christof GATTRINGER
on
21/6/2017
at
12:10
Through a careful study of smooth Wilson loop operators on the lattice, we are able to obtain very accurate confirmation of the $1/N^2$ scaling predicted by `t Hooft for the pure $\mathrm{SU}(N)$ gauge theory. We present our results for Wilson loops smoothed with the YangMills gradient flow and matched through the scale $t_0$.
This allows us to have renormalizable operators and test the $1/N^2$
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Presented by Mr. Miguel Francisco GARCÍA VERA
on
23/6/2017
at
15:00
While the sign problem of the Dirac fermion is conditioned by the positivity of a determinant, that of the Majorana fermion is conditioned by the positivity of a Pfaffian.
We introduce one sufficient condition for the positivity of a Pfaffian.
Based on the positivity condition, we study an effective model of the Majorana edge states in condensed matter physics.
We also present the application t
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Presented by Arata YAMAMOTO
on
21/6/2017
at
9:00
Many correlators in lattice QCD show an exponential degradation of the signaltonoise ratio with distance. This problem can be addressed by performing *multilevel* Monte Carlo sampling. However, to date, multilevel techniques have been limited to bosonic theories.
To overcome this limitation, we developed a factorization into independent spacetime domains of the Wilson fermions determinant con
... More
Presented by Dr. Marco CÈ
on
22/6/2017
at
15:20
In principle the loop equation provides a complete formulation of a gauge theory purely in terms of Wilson loops. In the case of lattice gauge theories the loop equation is a well defined equation for a discrete set of quantities and can be easily solved at strong coupling either numerically or by series expansion. At weak coupling, however, we argue that the equations are not well defined unless
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Presented by Prof. Martin KRUCZENSKI
on
21/6/2017
at
9:40
We analyze the CP(1) model using the Loop optimization for Tensor network renormalization (LoopTNR). This method makes it possible to completely remove shortrange entanglement at each coarsegraining step which can not be removed by the Tensor renormalization group. We compare the results of these methods in the presence of the theta term.
Presented by Mr. Hikaru KAWAUCHI
on
23/6/2017
at
17:30
The problem of finding a positive distribution, which corresponds to a given complex density in complex Langevin approach, is studied. By the requirement that the moments of the positive distribution and of the complex density are equal, one can reduce the problem to solving the matching conditions. After imposing the positivity of the distribution, these conditions become a set of quadratic equat
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Presented by Mr. Adam WYRZYKOWSKI
on
22/6/2017
at
18:30
The QCD at finite density is not well understood yet, where standard MonteCarlo simulation suffers from sign problem. In order to overcome the sign problem, the method of Lefschetz thimble has been explored. Basically, the original sign problem can be less severe in a complexified theory due to the constancy of the imaginary part of an action on each thimble. However, socalled global sign proble
... More
Presented by Shoichiro TSUTSUI
on
22/6/2017
at
17:30
We study the oneloop effective action defined by the chiral overlap operator in the 4dimensional lattice formulation of chiral gauge theories by Grabowska and Kaplan. In the treelevel continuum limit, the lefthanded component of the fermion is coupled only to the original gauge field~$A$, while the righthanded one is coupled only to~$A_\star$, which is given by the gradient flow of~$A$ with i
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Presented by Mr. Okuto MORIKAWA
on
23/6/2017
at
16:00
Classical realtime lattice simulations play an important role in understanding nonequilibrium phenomena in gauge theories and are used in particular to model the prethermal evolution of heavy
ion collisions. Above the Debye scale the classical YangMills (CYM) theory can be matched smoothly to kinetic theory. First we study the limits of the quasiparticle picture of the CYM fields by determini
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Presented by Mr. Jarkko PEURON
on
23/6/2017
at
17:10
A positive representation for a sample of complex densities is constructed.
In particular, complex measures on a direct product
of $U(1)$ groups are studied.
After identifying general conditions which such representations should satisfy, several concrete
realisations are proposed. Their performance is illustrated in few concrete examples
representing problems in abelian lattice gauge th
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Presented by Jacek WOSIEK
on
22/6/2017
at
17:10
It is an old idea to replace averages of observables with respect to complex weight by an average of its analytic continuation to complexified space with respect to some probabilistic measure. This is precisely what one would like to get from complex Langevin simulations. Unfortunately, these fail in many cases of physical interest. In my talk I will describe method of deriving positive representa
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Presented by Mr. Błażej RUBA
on
22/6/2017
at
17:50
Machine learning has been a fast growing field of research in several areas
dealing with large datasets. We report
recent progress on using RG ideas in the context of machine learning.
We discuss the correspondence between principal components analysis (PCA)
and RG flows across the transition for worm configurations of the 2D Ising model.
More generally, we discuss the relationship between
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Presented by Prof. Yannick MEURICE
on
23/6/2017
at
18:30
Quantum Finite Element (QFE) seeks to generalize lattice field theory to any smooth Euclidean Riemann manifold by adapting the Finite Elements Method (FEM) in the classical limit and the geometrical characterization of Regge Calculus, supplemented by counter terms required to cancel the local scheme due to ultraviolet divergences at simplicial cutoff. High precision numerical test are presented
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Presented by Prof. Richard BROWER
on
21/6/2017
at
12:30
Tensor Network methods have been established over the last decade as a powerful technique for the simulation of stronglycorrelated systems in low dimensions. Employing the formalism of Matrix Product States, we investigate the phase diagram of the massive Thirring model. Several distinct sectors of the total fermion number are observed. We discuss the interpretation of these sectors in the dual s
... More
Presented by Mr. David TaoLin TAN
on
23/6/2017
at
17:50
I discuss a method to define a thetaangle in 1+1D gauge theories with matter in a way which allows for a dual description without the sign problem. The method begins with noncompact gauge theory with a continuous Rvalued center symmetry. By gauging the center symmetry down to U(1), a natural thetaterm can be introduced through the gauge field for the center symmetry. The theory in this formula
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Presented by Dr. Tin SULEJMANPASIC
on
23/6/2017
at
16:50
We study the impact of the Gradient Flow on the topology in
various models. The topological susceptibility is measured
directly, and by the "slab method", which is based on the
topological content of subvolumes ("slabs").
The results obtained by both methods are consistent, but the
impact of the Gradient Flow on the characteristic quantity
of the slab method is different in 2flavor Q
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Presented by Mr. Hector MEJIADIAZ
on
23/6/2017
at
16:20
We describe our studies of truncation of the twisted formulation of fourdimensional lattice N=4 super YangMills from U(N) gauge theory to SU(N) gauge theory. One approach involves imposing the constraint that the complexified bosonic link matrices are elements of the group SL(N,C). We describe how this is consistent with SU(N) lattice gauge invariance. The second approach achieves this objective
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Presented by Prof. Joel GIEDT
on
21/6/2017
at
9:20
A continuum Lagrangian can be rewritten as an equivalent lattice action of discretely labelled variables. When the discrete variables come from wavelets, new possible criteria for acceptable actions open up.
Presented by Prof. Herbert NEUBERGER
on
21/6/2017
at
11:30