6,836 research outputs found
A non-equilibrium quantum Landauer principle
Using the operational framework of completely positive, trace preserving
operations and thermodynamic fluctuation relations, we derive a lower bound for
the heat exchange in a Landauer erasure process on a quantum system. Our bound
comes from a non-phenomenological derivation of the Landauer principle which
holds for generic non-equilibrium dynamics. Furthermore the bound depends on
the non-unitality of dynamics, giving it a physical significance that differs
from other derivations. We apply our framework to the model of a spin-1/2
system coupled to an interacting spin chain at finite temperature.Comment: 4 pages, 2 figures, RevTeX4-1; Accepted for publication in Phys. Rev.
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IRS II: a framework and infrastructure for semantic web services
In this paper we describe IRS–II (Internet Reasoning Service) a framework and implemented infrastructure, whose main goal is to support the publication, location, composition and execution of heterogeneous web services, augmented with semantic descriptions of their functionalities. IRS–II has three main classes of features which distinguish it from other work on semantic web services. Firstly, it supports one-click publishing of standalone software: IRS–II automatically creates the appropriate wrappers, given pointers to the standalone code. Secondly, it explicitly distinguishes between tasks (what to do) and methods (how to achieve tasks) and as a result supports capability-driven service invocation; flexible mappings between services and problem specifications; and dynamic, knowledge-based service selection. Finally, IRS–II services are web service compatible – standard web services can be trivially published through the IRS–II and any IRS–II service automatically appears as a standard web service to other web service infrastructures. In the paper we illustrate the main functionalities of IRS–II through a scenario involving a distributed application in the healthcare domain
Daemonic Ergotropy: Enhanced Work Extraction from Quantum Correlations
We investigate how the presence of quantum correlations can influence work
extraction in closed quantum systems, establishing a new link between the field
of quantum non-equilibrium thermodynamics and the one of quantum information
theory. We consider a bipartite quantum system and we show that it is possible
to optimise the process of work extraction, thanks to the correlations between
the two parts of the system, by using an appropriate feedback protocol based on
the concept of ergotropy. We prove that the maximum gain in the extracted work
is related to the existence of quantum correlations between the two parts,
quantified by either quantum discord or, for pure states, entanglement. We then
illustrate our general findings on a simple physical situation consisting of a
qubit system.Comment: 7 pages, 3 figures; RevTeX
Gordon Scott Fulcher: Renaissance Man of Glass Science
To a glass scientist, the name Fulcher conjures images of viscosity vs. temperature diagrams for glass-forming liquids. Indeed, Gordon Fulcher’s seminal 1925 publication, in which he proposed his three-parameter model of viscosity, is one of the most significant and influential papers ever published in the field of glass science. Fulcher developed this equation during the early part of his 14-year career at Corning Glass Works (1920-1934). However, Fulcher’s work in viscosity represents a small fraction of his highly diverse and accomplished career, which included pioneering the field of electrocast ceramics and developing the modern system of scientific abstracting that it still in use today. Fulcher also had a keen interest in social and economic problems, and his latter research focused heavily on the field of metacognition, i.e., the process of thinking
(WP 2024-01) Douglass North, New Institutional Economics, and Complexity Theory
Douglass North was central to the emergence of New Institutional Economics. Less well known are his later writings where he became interested in complexity theory. He attended the second economics complexity conference at the Santa Fe Institute in 1996 on how the economy functions as a complex adaptive system, and in his 2005 Understanding the Process of Economic Change incorporated this thinking into his argument that market systems depend on how institutions evolve. North also emphasized in the 2005 book the role belief played in evolutionary processes, and drew on cognitive science, especially the famous ‘scaffolding’ idea of cognitive scientist Andy Clark – the idea that the brain and the world ‘collaborate’ to address our computational and informational needs. This chapter discusses how North’s thinking about institutions and change reflected these later investigations. It concludes with comments on his late thoughts about the problem of violence
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