Joseph M. Renes

Last Name

Renes

First Name

Joseph M.

ORCID

0000-0003-2302-8025

Organisational unit

03781 - Renner, Renato / Renner, Renato

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Publications1 - 10 of 112

Coherent state contellations and polar codes for Bosonic Gaussian channels
Lacerda, Felipe; Renes, Joseph M.; Scholz, Volkher B. (2016)
arXiv
Second-order coding rates for pure-loss bosonic channels
Wilde, Mark M.; Renes, Joseph M.; Guha, Saikat (2016)
Quantum Information Processing
A Minimax Converse for Quantum Channel Coding
Renes, Joseph M. (2015)
arXiv
Symmetric extension in two-way quantum key distribution
Myhr, Geir O.; Renes, Joseph M.; Doherty, Andrew C.; et al. (2009)
Physical Review A
We introduce symmetric extensions of bipartite quantum states as a tool for analyzing protocols that distill secret key from quantum correlations. Whether the correlations are coming from a prepare-and-measure quantum key distribution scheme or from an entanglement-based scheme, the protocol has to produce effective states without a symmetric extension in order to succeed. By formulating the symmetric extension problem as a semidefinite program, we solve the problem for Bell-diagonal states. Applying this result to the six-state and Bennett-Brassard 1984 schemes, we show that for the entangled states that cannot be distilled by current key distillation procedures, the failure can be understood in terms of a failure to break a symmetric extension. ©2009 American Physical Society
Graph Neural Networks for Enhanced Decoding of Quantum LDPC Codes
Gong, Anqi; Cammerer, Sebastian; Renes, Joseph M. (2024)
2024 IEEE International Symposium on Information Theory (ISIT)
In this work, we propose a fully differentiable iterative decoder for quantum low-density parity-check (LDPC) codes. The proposed algorithm is composed of classical belief propagation (BP) decoding stages and intermediate graph neural network (GNN) layers. Both components of the decoder are defined over the same sparse decoding graph enabling a seamless integration and scalability to large codes. The core idea is to use the GNN component between consecutive BP runs so that the knowledge from the previous BP run can be leveraged to better initialize the next BP run. This enables the proposed decoder to learn to compensate for sub-optimal BP decoding graphs that result from the design constraints of quantum LDPC codes. Since the entire decoder remains differentiable, gradient descent-based training is possible. We compare the error rate performance of the proposed decoder against various post-processing methods such as random perturbation, enhanced feedback, augmentation, and ordered-statistics decoding (OSD) and show that a carefully designed training process lowers the error-floor significantly. As a result, our proposed decoder outperforms the former three methods using significantly fewer post-processing attempts. The source code of our experiments is available online.
Minimizing couplings in renormalization by preserving short-range mutual information
Bertoni, Christian; Renes, Joseph M. (2022)
Journal of Physics A: Mathematical and Theoretical
The connections between renormalization in statistical mechanics and information theory are intuitively evident, but a satisfactory theoretical treatment remains elusive. We show that the real space renormalization map that minimizes long range couplings in the renormalized Hamiltonian is, somewhat counterintuitively, the one that minimizes the loss of short-range mutual information between a block and its boundary. Moreover, we show that a previously proposed minimization focusing on preserving long-range mutual information is a relaxation of this approach, which indicates that the aims of preserving long-range physics and eliminating short-range couplings are related in a nontrivial way.
Quantum dichotomies and coherent thermodynamics beyond first-order asymptotics
Lipka-Bartosik, Patryk; Chubb, Christopher; Renes, Joseph M.; et al. (2023)
arXiv
We address the problem of exact and approximate transformation of quantum dichotomies in the asymptotic regime, i.e., the existence of a quantum channel E mapping ρ⊗n1 into ρ⊗Rnn2 with an error ϵn (measured by trace distance) and σ⊗n1 into σ⊗Rnn2 exactly, for a large number n. We derive second-order asymptotic expressions for the optimal transformation rate Rn in the small, moderate, and large deviation error regimes, as well as the zero-error regime, for an arbitrary pair (ρ1,σ1) of initial states and a commuting pair (ρ2,σ2) of final states. We also prove that for σ1 and σ2 given by thermal Gibbs states, the derived optimal transformation rates in the first three regimes can be attained by thermal operations. This allows us, for the first time, to study the second-order asymptotics of thermodynamic state interconversion with fully general initial states that may have coherence between different energy eigenspaces. Thus, we discuss the optimal performance of thermodynamic protocols with coherent inputs and describe three novel resonance phenomena allowing one to significantly reduce transformation errors induced by finite-size effects. What is more, our result on quantum dichotomies can also be used to obtain, up to second-order asymptotic terms, optimal conversion rates between pure bipartite entangled states under local operations and classical communication.
Time-Energy Uncertainty Relation for Noisy Quantum Metrology
Faist, Philippe; Woods, Mischa P.; Albert, Victor V.; et al. (2023)
PRX Quantum
Detection of very weak forces and precise measurement of time are two of the many applications of quantum metrology to science and technology. To sense an unknown physical parameter, one prepares an initial state of a probe system, allows the probe to evolve as governed by a Hamiltonian H for some time t, and then measures the probe. If H is known, we can estimate t by this method; if t is known, we can estimate classical parameters on which H depends. The accuracy of a quantum sensor can be limited by either intrinsic quantum noise or by noise arising from the interactions of the probe with its environment. In this work, we introduce and study a fundamental trade-off, which relates the amount by which noise reduces the accuracy of a quantum clock to the amount of information about the energy of the clock that leaks to the environment. Specifically, we consider an idealized scenario in which a party Alice prepares an initial pure state of the clock, allows the clock to evolve for a time that is not precisely known, and then transmits the clock through a noisy channel to a party Bob. Meanwhile, the environment (Eve) receives any information about the clock that is lost during transmission. We prove that Bob's loss of quantum Fisher information about the elapsed time is equal to Eve's gain of quantum Fisher information about a complementary energy parameter. We also prove a similar, but more general, trade-off that applies when Bob and Eve wish to estimate the values of parameters associated with two noncommuting observables. We derive the necessary and sufficient conditions for the accuracy of the clock to be unaffected by the noise, which form a subset of the Knill-Laflamme error-correction conditions. A state and its local time-evolution direction, if they satisfy these conditions, are said to form a metrological code. We provide a scheme to construct metrological codes in the stabilizer formalism. We show that there are metrological codes that cannot be written as a quantum error-correcting code with similar distance in which the Hamiltonian acts as a logical operator, potentially offering new schemes for constructing states that do not lose any sensitivity upon application of a noisy channel. We discuss applications of the trade-off relation to sensing using a quantum many-body probe subject to erasure or amplitude-damping noise.
Mark M. Wilde: Quantum information theory
Renes, Joseph M. (2014)
Quantum Information Processing
Coherent-state constellations and polar codes for thermal Gaussian channels
Lacerda, Felipe; Renes, Joseph M.; Scholz, Volkher B. (2017)
Physical Review A

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Joseph M. Renes

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