Publications associées à Central charge

Null energy constraints on two-dimensional RG flows

We study applications of spectral positivity and the averaged null energy condition (ANEC) to renormalization group (RG) flows in two-dimensional quantum field theory. We find a succinct new proof of the Zamolodchikov c-theorem, and derive further independ ...

Springer Nature2024

Spin, Charge, and ?-Spin Separation in One-Dimensional Photodoped Mott Insulators

Philipp Georg Werner Seeberger

We show that effectively cold metastable states in one-dimensional photodoped Mott insulators described by the extended Hubbard model exhibit spin, charge, and q-spin separation. Their wave functions in the large on-site Coulomb interaction limit can be ex ...

AMER PHYSICAL SOC2023

Two-point functions and bootstrap applications in quantum field theories

Denis Karateev

We study two-point functions of local operators and their spectral representation in UV complete quantum field theories in generic dimensions focusing on conserved currents and the stress-tensor. We establish the connection with the central charges of the ...

Springer Nature2022

Bootstrapping massive quantum field theories

Denis Karateev, João Miguel Augusto Penedones Fernandes

We propose a new non-perturbative method for studying UV complete unitary quantum field theories (QFTs) with a mass gap in general number of spacetime dimensions. The method relies on unitarity formulated as positive semi-definiteness of the matrix of inne ...

Springer Nature2020

Colliders and conformal interfaces

João Miguel Augusto Penedones Fernandes, Antonin Tancrède Amaury Rousset, Marco Meineri

We set up a scattering experiment of matter against an impurity which separates two generic one-dimensional critical quantum systems. We compute the flux of reflected and transmitted energy, thus defining a precise measure of the transparency of the interf ...

Springer Nature2020

Novel families of SU(N) AKLT states with arbitrary self-conjugate edge states

Frédéric Mila, Samuel Gozel

Using the Matrix Product State framework, we generalize the Affleck-Kennedy-Lieb-Tasaki (AKLT) construction to one-dimensional spin liquids with global color SU(N) symmetry, finite correlation lengths, and edge states that can belong to any self-conjugate ...

2019

Charting the space of 3D CFTs with a continuous global symmetry

João Miguel Augusto Penedones Fernandes, Alessandro Vichi

We study correlation functions of a conserved spin-1 current J in three dimensional Conformal Field Theories (CFTs). We investigate the constraints imposed by permutation symmetry and current conservation on the form of three point functions and the four p ...

Springer Nature2019

Quantum phase transitions beyond Landau-Ginzburg theory in one-dimensional space revisited

Christopher Marc Mudry

The phase diagram of the quantum spin-1/2 antiferromagnetic J(1)-J(2) XXZ chain was obtained by Haldane using bosonization techniques [Haldane, Phys. Rev. B 25, 4925 (1982); 26, 5257 (1982)]. It supports three distinct phases for 0

2019

Density matrix renormalization group simulations of SU(N) Heisenberg chains using standard Young tableaus: Fundamental representation and comparison with a finite-size Bethe ansatz

Frédéric Mila, Pierre Marcel Nataf

We develop an efficient method to perform density matrix renormalization group simulations of the SU(N) Heisenberg chain with open boundary conditions taking full advantage of the SU(N) symmetry of the problem. This method is an extension of the method pre ...

2018

Walking, Weak first-order transitions, and Complex CFTs II. Two-dimensional Potts model at Q > 4

Bernardo Zan, Victor Gorbenko

We study complex CFTs describing fixed points of the two-dimensional Q-state Potts model with Q > 4. Their existence is closely related to the weak first-order phase transition and the "walking" renormalization group (RG) behavior present in the real Potts ...

2018

Non-Abelian chiral spin liquid in a quantum antiferromagnet revealed by an iPEPS study

Abelian and non-Abelian topological phases exhibiting protected chiral edge modes are ubiquitous in the realm of the fractional quantum Hall (FQH) effect. Here, we investigate a spin-1 Hamiltonian on the square lattice which could, potentially, host the sp ...

2018

Exact diagonalization of HeisenbergSU(N)chains in the fully symmetric and antisymmetric representations

Frédéric Mila, Pierre Marcel Nataf

Motivated by recent experimental progress in the context of ultracold multicolor fermionic atoms in optical lattices, we have developed a method to exactly diagonalize the Heisenberg SU(N) Hamiltonian with several particles per site living in a fully symme ...

2016

Spontaneously broken mass

Solomon G Shamsuddin Osman Endlich

The Galilei group involves mass as a central charge. We show that the associated superselection rule is incompatible with the observed phenomenology of superfluid helium 4: this is recovered only under the assumption that mass is spontaneou.519 broken. Thi ...

Springer Nature2015

Antiferromagnetic Spin-S Chains with Exactly Dimerized Ground States

Frédéric Mila, Frédéric Alexis Michaud, Salvatore Manmana, François Vernay

We show that spin S Heisenberg spin chains with an additional three-body interaction of the form (Si-1 center dot S-i)(S-i center dot S-i (+) (1)) + H.c. possess fully dimerized ground states if the ratio of the three-body interaction to the bilinear one i ...

2012

Carving out the space of 4D CFTs

Alessandro Vichi

We introduce a new numerical algorithm based on semidefinite programming to efficiently compute bounds on operator dimensions, central charges, and OPT coefficients in 4D conformal and N = 1 superconformal field theories. Using our algorithm, we dramatical ...

Springer Nature2012

Tackling the Supersymmetric Flavour Problem in String Models

Christopher John Andrey

In this work we address one of the phenomenological issues of beyond the Standard Model scenarios which embed Supersymmetry, namely the Supersymmetric Flavour Problem, in the context of String Theory. Indeed, the addition of new interactions to the Standar ...

EPFL2011

A New Method to Explore Conformal Field Theories in Any Dimension

Alessandro Vichi

The thesis represents an investigation into Conformal Field Theories (CFT's) in arbitrary dimensions. We propose an innovative method to extract informations about CFT's in a quantitative way. Studying the crossing symmetry of the four point function of sc ...

EPFL2011

Spontaneous trimerization in a bilinear-biquadratic S=1 zig-zag chain

Recent theoretical studies raised the possibility of a realization of spin nematic states in the S = 1 triangular lattice compound NiGa2S4. We study the bilinear-biquadratic spin 1 chain in a zig-zag geometry by means of the density matrix renormalization ...

2007