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Table de caractères (mathématiques)

Publications associées (13)

Six-dimensional sphere packing and linear programming

Maryna Viazovska, Matthew De Courcy-Ireland, Maria Margarethe Dostert

We prove that the Cohn-Elkies linear programming bound for sphere packing is not sharp in dimension 6. The proof uses duality and optimization over a space of modular forms, generalizing a construction of Cohn- Triantafillou [Math. Comp. 91 (2021), pp. 491 ...

Amer Mathematical Soc2024

Six-dimensional sphere packing and linear programming

Maryna Viazovska, Matthew De Courcy-Ireland, Maria Margarethe Dostert

arXiv2022

Irvsp: To obtain irreducible representations of electronic states in the VASP

Quansheng Wu, Ziyi Wang

We present an open-source program irvsp, to compute irreducible representations of electronic states for all 230 space groups with an interface to the Vienna ab-initio Simulation Package. This code is fed with plane-wave-based wavefunctions (e.g. WAVECAR) ...

ELSEVIER2021

Mixed Dimensionality of Confined Conducting Electrons in the Surface Region of SrTiO3

Thorsten Schmitt, Joël Mesot, Johan Juul Chang, Martin Mansson, Elia Razzoli

Using angle-resolved photoemission spectroscopy, we show that the recently discovered surface state on SrTiO3 consists of nondegenerate t(2g) states with different dimensional characters. While the d(xy) bands have quasi-2D dispersions with weak k(z) depen ...

Amer Physical Soc2014

Arithmetic harmonic analysis on character and quiver Varieties II

Tamás Hausel

We study connections between the topology of generic character varieties of fundamental groups of punctured Riemann surfaces, Macdonald polynomials, quiver representations, Hilbert schemes on C-x x C-x, modular forms and multiplicities in tensor products o ...

Elsevier2013

Irreducible disconnected subgroups of exceptional algebraic groups

Soumaïa Nadia Ghandour

This paper studies the irreducible embeddings of simple algebraic groups of exceptional type. It is motivated by the role of such embeddings in the study of positive dimensional closed subgroups of classical algebraic groups. In this paper we give a classi ...

2010

Irreducibility of disconnected subgroups of exceptional algebraic groups

Soumaïa Nadia Ghandour

This dissertation is concerned with the study of irreducible embeddings of simple algebraic groups of exceptional type. It is motivated by the role of such embeddings in the study of positive dimensional closed subgroups of classical algebraic groups. The ...

EPFL2008

Computing the performance of unitary space-time group codes from their character table

Mohammad Amin Shokrollahi

Multiple antennas can greatly increase the data rate and reliability of a wireless communication link in a fading environment. Their success, however, depends on the design of cedes that achieve these promises. It is well known that unitary matrices can be ...

2002

Group characters and unitary space-time codes

Mohammad Amin Shokrollahi

Hassibi, Hochwald, Shokrollahi and Sweldens (see tech. rep., Bell Laboratories, Lucent Technologies, 2000) classified all finite groups of unitary matrices with nonzero diversity product. It is well-known, however, that differential space- time codes with ...

2001

Probing excitonic nonlinearities in quantum wires

Benoît Marie Joseph Deveaud, Andrea Crottini, Xiao Wang

We report on the experimental observation of excitonic molecules (biexcitons) in high-quality V-shaped quantum wires. By means of spatially resolved near-field photoluminescence spectroscopy, first we unambiguously isolate excitons with a one-dimensional c ...

2000

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