scholarly journals Gaussian states of continuous-variable quantum systems provide universal and versatile reservoir computing

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Johannes Nokkala ◽  
Rodrigo Martínez-Peña ◽  
Gian Luca Giorgi ◽  
Valentina Parigi ◽  
Miguel C. Soriano ◽  
...  
Keyword(s):  
Thermal Fluctuations ◽  
Continuous Variable ◽  
Quantum Systems ◽  
Full Potential ◽  
Reservoir Computing ◽  
Linear Dynamical Systems ◽  
Gaussian States ◽  
Proposed Model ◽  
Training Cost ◽  
The Rich

AbstractQuantum reservoir computing aims at harnessing the rich dynamics of quantum systems for machine-learning purposes. It can be used for online time series processing while having a remarkably low training cost. Here, we establish the potential of continuous-variable Gaussian states of linear dynamical systems for quantum reservoir computing. We prove that Gaussian resources are enough for universal reservoir computing. We find that encoding the input into Gaussian states is both a source and a means to tune the nonlinearity of the overall input-output map. We further show that the full potential of the proposed model can be reached by encoding to quantum fluctuations, such as squeezed vacuum, instead of classical fields or thermal fluctuations. Our results introduce a research paradigm for reservoir computing harnessing quantum systems and engineered Gaussian quantum states.

scholarly journals ENTANGLEMENT SHARING: FROM QUBITS TO GAUSSIAN STATES

2006 ◽  
Vol 04 (03) ◽  
pp. 383-393 ◽  
Author(s):  
GERARDO ADESSO ◽  
FABRIZIO ILLUMINATI
Keyword(s):  
Information Theory ◽  
Quantum Information ◽  
Quantum Correlations ◽  
Quantum Information Theory ◽  
Continuous Variable ◽  
Quantum Systems ◽  
Tripartite Entanglement ◽  
Gaussian States ◽  
Trade Off ◽  
Entanglement Sharing

It is a central trait of quantum information theory that there exist limitations to the free sharing of quantum correlations among multiple parties. Such monogamy constraints have been introduced in a landmark paper by Coffman, Kundu and Wootters, who derived a quantitative inequality expressing a trade-off between the couplewise and the genuine tripartite entanglement for states of three qubits. Since then, a lot of efforts have been devoted to the investigation of distributed entanglement in multipartite quantum systems. In this paper we report, in a unifying framework, a bird's eye view of the most relevant results that have been established so far on entanglement sharing in quantum systems. We will take off from the domain of N qubits, graze qudits, and finally land in the almost unexplored territory of multimode Gaussian states of continuous variable systems.

scholarly journals Double Slit with an Einstein–Podolsky–Rosen Pair

2020 ◽  
Vol 10 (3) ◽  
pp. 792 ◽  
Author(s):  
Bar Y. Peled ◽  
Amit Te’eni ◽  
Danko Georgiev ◽  
Eliahu Cohen ◽  
Avishy Carmi
Keyword(s):  
Continuous Variable ◽  
Quantum Systems ◽  
Quantum Measurements ◽  
Weak Measurements ◽  
Gaussian States ◽  
Bipartite Quantum Systems ◽  
Einstein Podolsky Rosen ◽  
Local Interference ◽  
Double Slit

In this somewhat pedagogical paper we revisit complementarity relations in bipartite quantum systems. Focusing on continuous-variable systems, we examine the influential class of EPR-like states through a generalization to Gaussian states and present some new quantitative relations between entanglement and local interference within symmetric and asymmetric double-double-slit scenarios. This approach is then related to ancilla-based quantum measurements, and weak measurements in particular. Finally, we tie up the notions of distinguishability, predictability, coherence and visibility while drawing some specific connections between them.

scholarly journals An efficient numerical approach for simulating contact in origami assemblages

2019 ◽  
Vol 475 (2230) ◽  
pp. 20190366 ◽  
Author(s):  
Yi Zhu ◽  
Evgueni T. Filipov
Keyword(s):  
Numerical Approach ◽  
Internal Force ◽  
Contact Forces ◽  
Model Parameters ◽  
Full Potential ◽  
Stationary Potential ◽  
Contact Potential ◽  
Proposed Model ◽  
Approach Infinity ◽  
Internal Force Vector

Origami-inspired structures provide novel solutions to many engineering applications. The presence of self-contact within origami patterns has been difficult to simulate, yet it has significant implications for the foldability, kinematics and resulting mechanical properties of the final origami system. To open up the full potential of origami engineering, this paper presents an efficient numerical approach that simulates the panel contact in a generalized origami framework. The proposed panel contact model is based on the principle of stationary potential energy and assumes that the contact forces are conserved. The contact potential is formulated such that both the internal force vector and the stiffness matrix approach infinity as the distance between the contacting panel and node approaches zero. We use benchmark simulations to show that the model can correctly capture the kinematics and mechanics induced by contact. By tuning the model parameters accordingly, this methodology can simulate the thickness in origami. Practical examples are used to demonstrate the validity, efficiency and the broad applicability of the proposed model.

Taking a stance on emotion: affect, sequence, and intersubjectivity in dialogic interaction

2012 ◽  
Vol 32 (4) ◽  
Author(s):  
John W. Du Bois ◽  
Elise Kärkkäinen
Keyword(s):  
Conversation Analysis ◽  
Continuous Variable ◽  
Special Issue ◽  
Strategic Ambiguity ◽  
Collaborative Practices ◽  
Sociocultural Linguistics ◽  
The Rich ◽  
Affective Display ◽  
Dialogic Interaction

AbstractThis paper explores the domain of affect and emotion as they arise in interaction, from the perspective of stance, sequence, and dialogicality. We seek to frame the issue of affective display as part of a larger concern with how co-participants in interaction construct the socioaffective and sociocognitive relations that organize their intersubjectivity, via collaborative practices of stance taking. We draw mainly on two research traditions, conversation analysis and the dialogic turn in sociocultural linguistics, focusing on their treatments of affect, emotion, and intersubjectivity. Key ideas from the respective approaches are the role of sequence in shaping the realization and interpretation of stance, and dialogic resonance as a process of alignment between subsequent stances. We present a view of stance as a triplex act, achieved through overt communicative means, in which participants evaluate something, and thereby position themselves, and thereby align with co-participants in interaction. Alignment is argued to operate as a continuous variable rather than a dichotomy, as participants subtly monitor and modulate the “stance differential” between them, while often maintaining a strategic ambiguity. Finally, we comment on the rich contributions to the study of stance, affect, and intersubjectivity in interaction made by the collaborators in this special issue.

scholarly journals Fidelity-based unitary operation-induced quantum correlation for continuous-variable systems

2019 ◽  
Vol 17 (04) ◽  
pp. 1950035
Author(s):  
Liang Liu ◽  
Xiaofei Qi ◽  
Jinchuan Hou
Keyword(s):  
Quantum Correlation ◽  
Quantum Correlations ◽  
Continuous Variable ◽  
Gaussian Channel ◽  
Simple Computation ◽  
Gaussian States ◽  
Text Mode ◽  
Computation Formula ◽  
Geometric Measurement ◽  
Thermal States

We propose a measure of nonclassical correlation [Formula: see text] in terms of local Gaussian unitary operations based on square of the fidelity [Formula: see text] for bipartite continuous-variable systems. This quantity is easier to be calculated or estimated and is a remedy for the local ancilla problem associated with the geometric measurement-induced nonlocality. A simple computation formula of [Formula: see text] for any [Formula: see text]-mode Gaussian states is presented and an estimation of [Formula: see text] for any [Formula: see text]-mode Gaussian states is given. For any [Formula: see text]-mode Gaussian states, [Formula: see text] does not increase after performing a local Gaussian channel on the unmeasured subsystem. Comparing [Formula: see text] in scale with other quantum correlations such as Gaussian geometric discord for two-mode symmetric squeezed thermal states reveals that [Formula: see text] is much better in detecting quantum correlations of Gaussian states.

scholarly journals Koopman wavefunctions and classical–quantum correlation dynamics

2019 ◽  
Vol 475 (2229) ◽  
pp. 20180879 ◽  
Author(s):  
Denys I. Bondar ◽  
François Gay-Balmaz ◽  
Cesare Tronci
Keyword(s):  
Hamiltonian Structure ◽  
Classical System ◽  
Solvable Model ◽  
Infinite Family ◽  
Dynamical Theory ◽  
Quantum Systems ◽  
Von Neumann ◽  
Proposed Model ◽  
Exactly Solvable ◽  
Classical Quantum

Upon revisiting the Hamiltonian structure of classical wavefunctions in Koopman–von Neumann theory, this paper addresses the long-standing problem of formulating a dynamical theory of classical–quantum coupling. The proposed model not only describes the influence of a classical system onto a quantum one, but also the reverse effect—the quantum backreaction. These interactions are described by a new Hamiltonian wave equation overcoming shortcomings of currently employed models. For example, the density matrix of the quantum subsystem is always positive definite. While the Liouville density of the classical subsystem is generally allowed to be unsigned, its sign is shown to be preserved in time for a specific infinite family of hybrid classical–quantum systems. The proposed description is illustrated and compared with previous theories using the exactly solvable model of a degenerate two-level quantum system coupled to a classical harmonic oscillator.

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