Gian Luca Giorgi

Publications : 137
Aldex : 60
H-index : 24
Citations : 1904


Reconciling phase diffusion and Hartree–Fock approximation in condensate systems

Gian Luca Giorgi, Ferdinando de Pasquale

Jan 1, 2012 in Physica A: Statistical Mechanics and its Applications
Despite the weakly interacting regime, the physics of Bose–Einstein condensates is widely affected by particle–particle interactions. They determine quantum phase diffusion, which is known to be the main cause of loss of coherence. Studying a simple model of two interacting Bose systems, we show how to predict the appearance of phase diffusion beyond the Bogoliubov approximation, providing a self-...

Scalable photonic platform for real-time quantum reservoir computing

Jorge García-Beni et 4 al.

Jul 28, 2022 in Arxiv
Quantum Reservoir Computing (QRC) exploits the information processing capabilities of quantum systems to solve non-trivial temporal tasks, improving over their classical counterparts. Recent progress has shown the potential of QRC exploiting the enlarged Hilbert space, but real-time processing and the achievement of a quantum advantage with efficient use of resources are prominent challenges towar...

Quantum associative memory with a single driven-dissipative non-linear oscillator

Adrià Labay-Mora et 3 al.

May 19, 2022 in Arxiv
Algorithms for associative memory typically rely on a network of many connected units. The prototypical example is the Hopfield model, whose generalizations to the quantum realm are mainly based on open quantum Ising models. We propose a realization of associative memory with a single driven-dissipative quantum oscillator exploiting its infinite degrees of freedom in phase space. The model can imp...

Time Series Quantum Reservoir Computing with Weak and Projective Measurements

Pere Mujal et 5 al.

May 13, 2022 in Arxiv
Quantum machine learning represents a promising avenue for data processing, also for purposes of sequential temporal data analysis, as recently proposed in quantum reservoir computing (QRC). The possibility to operate on several platforms and noise intermediate-scale quantum devices makes QRC a timely topic. A challenge that has not been addressed yet, however, is how to efficiently include quantu...


Collision Models Can Efficiently Simulate Any Multipartite Markovian Quantum Dynamics.

Marco Cattaneo et 5 al.

Apr 2, 2021 in Physical review letters
We introduce the multipartite collision model, defined in terms of elementary interactions between subsystems and ancillas, and show that it can simulate the Markovian dynamics of any multipartite open quantum system. We develop a method to estimate an analytical error bound for any repeated interactions model, and we use it to prove that the error of our scheme displays an optimal scaling. Finall...

Multipartite quantum and classical correlations in symmetric n-qubit mixed states

Gian Luca Giorgi, Steve Campbell

Sep 3, 2014 in Arxiv
We discuss how to calculate genuine multipartite quantum and classical correlations in symmetric, spatially invariant, mixed $n$-qubit density matrices. We show that the existence of symmetries greatly reduces the amount of free parameters to be optimized in order to find the optimal measurement that minimizes the conditional entropy in the discord calculation. We apply this approach to the states...

Topological Protection and Control of Quantum Markovianity

Gian Luca Giorgi et 3 al.

Feb 11, 2020 in Arxiv
Under the Born--Markov approximation, a qubit system, such as a two-level atom, is known to undergo a memoryless decay of quantum coherence or excitation when weakly coupled to a featureless environment. Recently, it has been shown that unavoidable disorder in the environment is responsible for non-Markovian effects and information backflow from the environment into the system owing to Anderson lo...

Microscopic and phenomenological models of driven systems in structured reservoirs

Gian Luca Giorgi, Bruno Bellomo et 4 al.

Aug 8, 2019 in Arxiv
We study the paradigmatic model of a qubit interacting with a structured environment and driven by an external field by means of a microscopic and a phenomenological model. The validity of the so-called fixed-dissipator (FD) assumption, where the dissipation is taken as the one of the undriven qubit is discussed. In the limit of a flat spectrum, the FD model and the microscopic one remarkably prac...

Quantum state transfer in the presence of non homogeneous external potentials

Gian Luca Giorgi, Thomas Busch

Sep 13, 2013 in Arxiv
Heisenberg-type spin models in the limit of a low number of excitations are useful tools to study basic mechanisms in strongly correlated and magnetic systems. Many of these mechanisms can be experimentally tested using ultracold atoms. Here, we discuss the implementation of a quantum state transfer protocol in a tight-binding chain in the presence of an inhomogeneous external potential. We show t...

Quantum discord and remote state preparation

Gian Luca Giorgi

Jun 28, 2013 in Arxiv
The role played by quantum discord in mixed-state computation is widely debated since, in spite of evidence of its importance in creating quantum advantages, even in the absence of entanglement, there are not direct proofs of its necessity in these computational tasks. Recently the presence of discord was shown to be necessary and sufficient for remote state preparation for a broad class of quantu...

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