Publications related to Exact sequence

Eight-vertex criticality in the interacting Kitaev chain

We show that including pairing and repulsion into the description of one-dimensional spinless fermions, as in the domain wall theory of commensurate melting or the interacting Kitaev chain, leads, for strong enough repulsion, to a line of critical points i ...

AMER PHYSICAL SOC2023

Characteristic classes as complete obstructions

Martina Rovelli

In the first part of this paper, we propose a uniform interpretation of characteristic classes as obstructions to the reduction of the structure group and to the existence of an equivariant extension of a certain homomorphism defined a priori only on a sin ...

SPRINGER HEIDELBERG2019

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

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

Towards new invariants for principal bundles

Martina Rovelli

We investigate the theory of principal bundles from a homotopical point of view. In the first part of the thesis, we prove a classification of principal bundles over a fixed base space, dual to the well-known classification of bundles with a fixed structur ...

EPFL2017

KRAB zinc finger proteins

Didier Trono, Gabriela Ecco, Michaël Imbeault

Kruppel-associated box domain zinc finger proteins (KRAB-ZFPs) are the largest family of transcriptional regulators in higher vertebrates. Characterized by an N-terminal KRAB domain and a C-terminal array of DNA-binding zinc fingers, they participate, toge ...

2017

Exact diagonalization of SU( N ) Heisenberg and Affleck-Kennedy-Lieb-Tasaki chains using the full SU( N ) symmetry

Frédéric Mila, Pierre Marcel Nataf, Kianna Wan

We present a method for the exact diagonalization of the SU(N) Heisenberg interaction Hamiltonian using Young tableaus to work directly in each irreducible representation of the global SU(N) group. This generalized scheme is applicable to chains consisting ...

2017

Cellular Homotopy Excision

Kay Remo Werndli

There is a classical "duality" between homotopy and homology groups in that homotopy groups are compatible with homotopy pullbacks (every homotopy pullback gives rise to a long exact sequence in homotopy), while homology groups are compatible with homotopy ...

EPFL2016

Plaquette order in the SU(6) Heisenberg model on the honeycomb lattice

Frédéric Mila, Karlo Penc, Pierre Marcel Nataf, Miklos Lajko

We revisit the SU(6) Heisenberg model on the honeycomb lattice, which has been predicted to be a chiral spin liquid by mean-field theory [G. Szirmai et al., Phys. Rev. A 84, 011611(R) (2011)]. Using exact diagonalizations of finite clusters, infinite proje ...

2016

Thermal transport in low dimensions

Andrea Cepellotti

Lattice vibrations are the microscopic mechanism responsible for a large, if not dominant, contribution to heat transport in crystalline insulators. These vibrations are described in terms of phonons, collective excitations (or quasiparticles) in the form ...

EPFL2016

Real Space Imaging of Spin Polarons in Zn-Doped SrCu2(BO3)(2)

Frédéric Mila

We report on the real space profile of spin polarons in the quasi-two-dimensional frustrated dimer spin system SrCu2(BO3)(2) doped with 0.16% of Zn. The B-11 nuclear magnetic resonance spectrum exhibits 15 additional boron sites near nonmagnetic Zn impurit ...

2015

Multiscattering-enhanced optical probes for biosensing

Volodymyr Koman

Although reactive oxygen species (ROS) are an inescapable part of every living organism, we are only beginning to understand their functions and mechanics. As of now, we know that ROS are involved in cell signalling, stress-response and defence against pat ...

EPFL2015

From Environmental Sequences to Morphology: Observation and Characterisation of a Paulinellid Testate Amoeba (Micropyxidiella edaphonis gen. nov. sp. nov. Euglyphida, Paulinellidae) from Soil using Fluorescent in situ Hybridization

Enrique Lara, Sonia Estelle Tarnawski

High microbial diversity is revealed by environmental DNA surveys. However, nothing is known about the morphology and function of these potentially new organisms. In the course of an environmental soil diversity study, we found for the first time environme ...

Elsevier2015

Multi-Commodity Network Flow for Tracking Multiple People

Pascal Fua, François Fleuret, Jérôme Berclaz, Horesh Beny Ben Shitrit

In this paper, we show that tracking multiple people whose paths may intersect can be formulated as a multi-commodity network flow problem. Our proposed framework is designed to exploit image appearance cues to prevent identity switches. Our method is effe ...

Institute of Electrical and Electronics Engineers2014

Quantum dimer model for the spin-1/2 kagome Z(2) spin liquid

Frédéric Mila, Ioannis Rousochatzakis

We revisit the description of the low-energy singlet sector of the spin-1/2 Heisenberg antiferromagnet on kagome in terms of an effective quantum dimer model. With the help of exact diagonalizations of appropriate finite-size clusters, we show that the emb ...

2014

Long-lasting fibrin matrices ensure stable and functional angiogenesis by highly tunable, sustained delivery of recombinant VEGF(164)

Jeffrey Alan Hubbell, Veronica Sacchi, Mikaël Martino, Kristen Lorentz, Martin Ehrbar, Elena Groppa

Clinical trials of therapeutic angiogenesis by vascular endothelial growth factor (VEGF) gene delivery failed to show efficacy. Major challenges include the need to precisely control in vivo distribution of growth factor dose and duration of expression. Re ...

National Academy of Sciences2014

Exact Diagonalization of Heisenberg SU(N) Models

Frédéric Mila, Pierre Marcel Nataf

Building on advanced results on permutations, we show that it is possible to construct, for each irreducible representation of SU(N), an orthonormal basis labeled by the set of standard Young tableaux in which the matrix of the Heisenberg SU(N) model (the ...

2014

Realization of higher Wess-Zumino-Witten models in spin chains

Frédéric Mila, Frédéric Alexis Michaud, Salvatore Manmana

Building on the generalization of the exactly dimerized Majumdar-Ghosh ground state to arbitrary spin S for the Heisenberg chain with a three-site term (Si-1 . S-i)(S-i . Si+1) + H.c., we use density-matrix renormalization group simulations and exact diago ...

2013

A DC power flow extension

Sidi-Rachid Cherkaoui, Maher Kayal, Theodoros Kyriakidis

In this work an extension of the well-known DC power flow method is presented. A normal DC power flow of the system is executed to determine voltage angles and a novel derivation of voltage amplitudes is devised. The latter is rigorously formulated and eig ...

IEEE2013

Competing states in the SU(3) Heisenberg model on the honeycomb lattice: Plaquette valence-bond crystal versus dimerized color-ordered state

Frédéric Mila, Karlo Penc, Miklos Lajko

Conflicting predictions have been made for the ground state of the SU(3) Heisenberg model on the honeycomb lattice: Tensor network simulations found a plaquette order [Zhao et al., Phys. Rev. B 85, 134416 (2012)], where singlets are formed on hexagons, whi ...

2013