Concept

Quantifications canoniques

Publications associées (26)

Convex Quantization Preserves Logconcavity

A logconcave likelihood is as important to proper statistical inference as a convex cost function is important to variational optimization. Quantization is often disregarded when writing likelihood models, ignoring the limitations of the physical detectors ...

IEEE Institute of Electrical and Electronics Engineers2022

Wigner Formulation of Thermal Transport in Solids

Nicola Marzari, Michele Simoncelli

Two different heat-transport mechanisms are discussed in solids. In crystals, heat carriers propagate and scatter particlelike as described by Peierls's formulation of the Boltzmann transport equation for phonon wave packets. In glasses, instead, carriers ...

American Physical Society2022

Semiclassical methods in conformal field theories scrutinized by the epsilon-expansion

Gil Badel

Conformal Field Theories (CFTs) are crucial for our understanding of Quantum Field Theory (QFT). Because of their powerful symmetry properties, they play the role of signposts in the space of QFTs. Any method that gives us information about their structure ...

EPFL2022

Quantum coherent microwave-optical transduction using high-overtone bulk acoustic resonances

Tobias Kippenberg

A device capable of converting single quanta of the microwave field to the optical domain is an outstanding endeavor in the context of quantum interconnects between distant superconducting qubits, but likewise can have applications in other fields, such as ...

AMER PHYSICAL SOC2021

Finite-Level Quantization Procedures for Construction and Decoding of Polar Codes

Emre Telatar, Yunus Inan

We consider finite-level, symmetric quantization procedures for construction and decoding of polar codes. Whether polarization occurs in the presence of quantization is not known in general. In [1], it is shown that a simple three-level quantization proced ...

IEEE2020

Implications of ANEC for SCFTs in four dimensions

Andrea Manenti, Alessandro Vichi

We explore consequences of the Averaged Null Energy Condition (ANEC) for scaling dimensions Delta of operators in four-dimensional N = 1 superconformal field theories. We show that in many cases the ANEC bounds are stronger than the corresponding unitarity ...

Springer Nature2020

Optimized Quantization in Distributed Graph Signal Filtering

Pascal Frossard, Isabela Cunha Maia Nobre

Distributed graph signal processing algorithms require the network nodes to communicate by exchanging messages in order to achieve a common objective. These messages have a finite precision in realistic networks, which may necessitate to implement message ...

2019

The S-matrix bootstrap. Part III: higher dimensional amplitudes

João Miguel Augusto Penedones Fernandes, Jonathan Campbell Toledo

We consider constraints on the S-matrix of any gapped, Lorentz invariant quantum field theory in 3+1 dimensions due to crossing symmetry, analyticity and unitarity. We extremize cubic couplings, quartic couplings and scattering lengths relevant for the ela ...

Springer Nature2019

Optimized Quantization in Distributed Graph Signal Processing

Pascal Frossard, Isabela Cunha Maia Nobre

Distributed graph signal processing methods require that the graph nodes communicate by exchanging messages. These messages have a finite precision in a realistic network, which may necessitate to implement quantization. Quantization, in turn, generates er ...

IEEE2019

Methods and apparatuses for encoding and decoding digital images or video streams

Pascal Frossard, Ntorina Thanou, Giulia Fracastoro

The invention relates to a method and an apparatus for encoding and/or decoding digital images, wherein said encoding apparatus (1100) comprises processing means (1110) configured for determining weights of a graph related to an image by minimizing a cost ...

2018

Heat kernel methods for Lifshitz theories

Diego Blas Temino, Mario Herrero Valea

We study the one-loop covariant effective action of Lifshitz theories using the heat kernel technique. The characteristic feature of Lifshitz theories is an anisotropic scaling between space and time. This is enforced by the existence of a preferred foliat ...

Springer Nature2017

Semiclassics, Goldstone bosons and CFT data

Riccardo Rattazzi, Alexander Monin, David Pirtskhalava, Fiona Katharina Seibold

Hellerman et al. (arXiv:1505.01537) have shown that in a generic CFT the spectrum of operators carrying a large U(1) charge can be analyzed semiclassically in an expansion in inverse powers of the charge. The key is the operator state correspondence by whi ...

Springer Nature2017

Quantization Design for Distributed Optimization

Colin Neil Jones, Ye Pu, Melanie Nicole Zeilinger

We consider the problem of solving a distributed optimization problem using a distributed computing platform, where the communication in the network is limited: each node can only communicate with its neighbors and the channel has a limited data-rate. A co ...

2017

Noether Theorems and Quantum Anomalies

Tudor Ratiu

A quantum anomaly is the breaking of symmetry with respect to some transformations after the quantization of a classical Hamiltonian or Lagrangian system. It is shown that both the Noether theorems (including their infinite-dimensional versions) and the ex ...

Springer Verlag2017

Estimation of transverse spin penetration length using second-harmonic measurement: Proposal of an experimental method

Jean-Philippe Ansermet

A theoretical description of spin current injection from a nonmagnetic layer into a magnetic one is presented, with the main emphasis on the description and determination of the penetration depth of spin current component transverse to the magnetization. T ...

Amer Physical Soc2016

Geometry-driven quantization for omnidirectional image coding

Pascal Frossard, Francesca De Simone

In this paper we propose a method to adapt the quantization tables of typical block-based transform codecs when the input to the encoder is a panoramic image resulting from equirectangular projection of a spherical image. When the visual content is project ...

2016

From the free surface flow of a viscoelastic fluid towards the elastic deformation of a solid

Marco Picasso

The free surface flow of an Oldroyd-B viscoelastic fluid is considered, following A. Bonito, M. Picasso, and M. Laso (2006)[1]. When removing a term in the extra-stress constitutive relation, the description of an elastic incompressible solid is obtained, ...

Elsevier France-Editions Scientifiques Medicales Elsevier2016

Optimal polynomial blow up range for critical wave maps

Joachim Krieger, Can Gao

We prove that the critical Wave Maps equation with target

S^2

and origin

\R^{2+1}

admits energy class blow up solutions of the form

u(t, r) = Q(\lambda(t)r) + \eps(t, r)

where

Q:\R^2\rightarrow S^2

is the ground state harmonic map and $\lambd ...

2015

Optimal polynomial blow up range for critical wave maps

Can Gao

We prove that the critical Wave Maps equation with target

S^2

and origin ℝ

^{2+1}

admits energy class blow up solutions of the form [ u(t, r) = Q(\lambda(t)r) + \epsilon(t, r) ] where

Q:ℝ²\rightarrow S^2

is the ground state harmonic map and $\lambda ...

EPFL2015

Phase properties of operator valued measures in phase space

Vivishek Sudhir

The Wigner phase operator (WPO) is identified as an operator valued measure (OVM) and its eigenstates are obtained. An operator satisfying the canonical commutation relation with the Wigner phase operator is also constructed and this establishes a Wigner d ...

Taylor & Francis Ltd2013