Special Issue "Physical Information and the Physical Foundations of Computation"

A special issue of Entropy (ISSN 1099-4300).

Deadline for manuscript submissions: closed (31 January 2021).

Special Issue Editor

Prof. Neal G. Anderson
E-Mail Website
Guest Editor
Department of Electrical & Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003-9292, USA
Interests: fundamental physical understanding of information and computation, physical-information theories, energy efficiency of computation, fundamental physical limits in computation, post-CMOS nanocomputing and other unconventional and natural computing paradigms

Special Issue Information

Dear Colleagues,

Nearly six decades have passed since Landauer declared that “information is physical” and proposed a fundamental thermodynamic link between information erasure and heat generation in computing processes. While Landauer’s ideas have been extensively analyzed, interpreted, and critiqued from multiple perspectives and have been generalized and extended within various physical theories of information and computation, they remain stubbornly controversial. This is a symptom of a broader and somewhat ironic predicament: Deep in this information age, we have highly sophisticated and widely used models of computing machines as physical systems, but we remain without a comprehensive and widely accepted fundamental understanding of computation as a distinct physical process with information as its physical currency. Without such an understanding, we cannot expect consensus resolution of contested claims associated with the physicality of information or, more generally, claim an established physical foundation for computation.

This Special Issue aims to clarify and advance the physical understanding of information and computation. We invite a broad range of original, high-quality contributions from a variety of disciplinary perspectives—including but not limited to engineering, physics, computer science, neuroscience, information science, biological physics, and the philosophy of science—that explicitly address fundamental links between physics, information, and computation. Submissions are welcome on all topics that serve to clarify and illuminate the physical dimensions of information and computation, codify them in physical definitions and theories, and reveal their consequences and implications.

Prof. Neal G. Anderson
Guest Editor

Manuscript Submission Information 

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Entropyis an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions. For invited papers by the Guest Editor which are submitted before 31 December 2020, we can apply a discount of 200 CHF. Please also note that for papers submitted after 31 December 2020 an APC of 1800 CHF applies.

Keywords

  • Physical conceptions, definitions, and measures of information (entropic and otherwise)
  • Physical conceptions, definitions, and measures of computation (thermodynamic and otherwise)
  • Physical information in specific computing contexts (digital, analog, natural, reversible, quantum, neural)
  • Distinctions between physical dynamics, information processing, and computation
  • Observer- and user-dependent notions of information and computation and their formal physical description
  • Fundamental physical limits and resource requirements for computation
  • Fluctuations and noise in physical information and computation
  • New perspectives on Landauer’s Principle, Maxwell’s Demon, and other controversial issues, including paths toward resolution
  • Other topics that explicitly address links between physics, information, and computation, including substantiated denials of such links

Published Papers (5 papers)

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Research

Open AccessArticle
Physical Limitations on Fundamental Efficiency of SET-Based Brownian Circuits
Entropy 2021, 23(4), 406; https://doi.org/10.3390/e23040406 - 30 Mar 2021
Viewed by 343
Abstract
Brownian circuits are based on a novel computing approach that exploits quantum fluctuations to increase the efficiency of information processing in nanoelectronic paradigms. This emerging architecture is based on Brownian cellular automata, where signals propagate randomly, driven by local transition rules, and can [...] Read more.
Brownian circuits are based on a novel computing approach that exploits quantum fluctuations to increase the efficiency of information processing in nanoelectronic paradigms. This emerging architecture is based on Brownian cellular automata, where signals propagate randomly, driven by local transition rules, and can be made to be computationally universal. The design aims to efficiently and reliably perform primitive logic operations in the presence of noise and fluctuations; therefore, a Single Electron Transistor (SET) device is proposed to be the most appropriate technology-base to realize these circuits, as it supports the representation of signals that are token-based and subject to fluctuations due to the underlying tunneling mechanism of electric charge. In this paper, we study the physical limitations on the energy efficiency of the Single-Electron Transistor (SET)-based Brownian circuit elements proposed by Peper et al. using SIMON 2.0 simulations. We also present a novel two-bit sort circuit designed using Brownian circuit primitives, and illustrate how circuit parameters and temperature affect the fundamental energy-efficiency limitations of SET-based realizations. The fundamental lower bounds are obtained using a physical-information-theoretic approach under idealized conditions and are compared against SIMON 2.0 simulations. Our results illustrate the advantages of Brownian circuits and the physical limitations imposed on their SET-realizations. Full article
(This article belongs to the Special Issue Physical Information and the Physical Foundations of Computation)
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Open AccessArticle
Conditional Action and Imperfect Erasure of Qubits
Entropy 2021, 23(3), 289; https://doi.org/10.3390/e23030289 - 26 Feb 2021
Viewed by 394
Abstract
We consider state changes in quantum theory due to “conditional action” and relate these to the discussion of entropy decrease due to interventions of “intelligent beings” and the principles of Szilard and Landauer/Bennett. The mathematical theory of conditional actions is a special case [...] Read more.
We consider state changes in quantum theory due to “conditional action” and relate these to the discussion of entropy decrease due to interventions of “intelligent beings” and the principles of Szilard and Landauer/Bennett. The mathematical theory of conditional actions is a special case of the theory of “instruments”, which describes changes of state due to general measurements and will therefore be briefly outlined in the present paper. As a detailed example, we consider the imperfect erasure of a qubit that can also be viewed as a conditional action and will be realized by the coupling of a spin to another small spin system in its ground state. Full article
(This article belongs to the Special Issue Physical Information and the Physical Foundations of Computation)
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Open AccessArticle
Computational Abstraction
Entropy 2021, 23(2), 213; https://doi.org/10.3390/e23020213 - 10 Feb 2021
Viewed by 562
Abstract
Representation and abstraction are two of the fundamental concepts of computer science. Together they enable “high-level” programming: without abstraction programming would be tied to machine code; without a machine representation, it would be a pure mathematical exercise. Representation begins with an abstract structure [...] Read more.
Representation and abstraction are two of the fundamental concepts of computer science. Together they enable “high-level” programming: without abstraction programming would be tied to machine code; without a machine representation, it would be a pure mathematical exercise. Representation begins with an abstract structure and seeks to find a more concrete one. Abstraction does the reverse: it starts with concrete structures and abstracts away. While formal accounts of representation are easy to find, abstraction is a different matter. In this paper, we provide an analysis of data abstraction based upon some contemporary work in the philosophy of mathematics. The paper contains a mathematical account of how Frege’s approach to abstraction may be interpreted, modified, extended and imported into type theory. We argue that representation and abstraction, while mathematical siblings, are philosophically quite different. A case of special interest concerns the abstract/physical interface which houses both the physical representation of abstract structures and the abstraction of physical systems. Full article
(This article belongs to the Special Issue Physical Information and the Physical Foundations of Computation)
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Open AccessArticle
Coherence and Entanglement Dynamics in Training Variational Quantum Perceptron
Entropy 2020, 22(11), 1277; https://doi.org/10.3390/e22111277 - 11 Nov 2020
Cited by 1 | Viewed by 495
Abstract
In quantum computation, what contributes supremacy of quantum computation? One of the candidates is known to be a quantum coherence because it is a resource used in the various quantum algorithms. We reveal that quantum coherence contributes to the training of variational quantum [...] Read more.
In quantum computation, what contributes supremacy of quantum computation? One of the candidates is known to be a quantum coherence because it is a resource used in the various quantum algorithms. We reveal that quantum coherence contributes to the training of variational quantum perceptron proposed by Y. Du et al., arXiv:1809.06056 (2018). In detail, we show that in the first part of the training of the variational quantum perceptron, the quantum coherence of the total system is concentrated in the index register and in the second part, the Grover algorithm consumes the quantum coherence in the index register. This implies that the quantum coherence distribution and the quantum coherence depletion are required in the training of variational quantum perceptron. In addition, we investigate the behavior of entanglement during the training of variational quantum perceptron. We show that the bipartite concurrence between feature and index register decreases since Grover operation is only performed on the index register. Also, we reveal that the concurrence between the two qubits of index register increases as the variational quantum perceptron is trained. Full article
(This article belongs to the Special Issue Physical Information and the Physical Foundations of Computation)
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Open AccessArticle
Blind Witnesses Quench Quantum Interference without Transfer of Which-Path Information
Entropy 2020, 22(7), 776; https://doi.org/10.3390/e22070776 - 16 Jul 2020
Viewed by 799
Abstract
Quantum computation is often limited by environmentally-induced decoherence. We examine the loss of coherence for a two-branch quantum interference device in the presence of multiple witnesses, representing an idealized environment. Interference oscillations are visible in the output as the magnetic flux through the [...] Read more.
Quantum computation is often limited by environmentally-induced decoherence. We examine the loss of coherence for a two-branch quantum interference device in the presence of multiple witnesses, representing an idealized environment. Interference oscillations are visible in the output as the magnetic flux through the branches is varied. Quantum double-dot witnesses are field-coupled and symmetrically attached to each branch. The global system—device and witnesses—undergoes unitary time evolution with no increase in entropy. Witness states entangle with the device state, but for these blind witnesses, which-path information is not able to be transferred to the quantum state of witnesses—they cannot “see” or make a record of which branch is traversed. The system which-path information leaves no imprint on the environment. Yet, the presence of a multiplicity of witnesses rapidly quenches quantum interference. Full article
(This article belongs to the Special Issue Physical Information and the Physical Foundations of Computation)
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