Hasil untuk "Information theory"

Y. Sekino, L. Susskind

We consider the problem of how fast a quantum system can scramble (thermalize) information, given that the interactions are between bounded clusters of degrees of freedom; pairwise interactions would be an example. Based on previous work, we conjecture: 1) The most rapid scramblers take a time logarithmic in the number of degrees of freedom. 2) Matrix quantum mechanics (systems whose degrees of freedom are n by n matrices) saturate the bound. 3) Black holes are the fastest scramblers in nature. The conjectures are based on two sources, one from quantum information theory, and the other from the study of black holes in String Theory.

G. Nair, F. Fagnani, S. Zampieri et al.

B. Zimmerman, D. Schunk

Robin I. M. Dunbar

K. Eisenhardt

C. Rovelli

I suggest that the common unease with taking quantum mechanics as a fundamental description of nature (the “measurement problem”) could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer-independent time. I suggest that this incorrect notion that generates the unease with quantum mechanics is the notion of “observer-independent state” of a system, or “observer-independent values of physical quantities.” I reformulate the problem of the “interpretation of quantum mechanics” as the problem of deriving the formalism from a set of simple physical postulates. I consider a reformulation of quantum mechanics in terms of information theory. All systems are assumed to be equivalent, there is no observer-observed distinction, and the theory describes only the information that systems have about each other; nevertheless, the theory is complete.

A. Church

J. Bradbury, S. Vehrencamp

A. Yao

G. Vidal, José I. Latorre, E. Rico et al.

Entanglement, one of the most intriguing features of quantum theory and a main resource in quantum information science, is expected to play a crucial role also in the study of quantum phase transitions, where it is responsible for the appearance of long-range correlations. We investigate, through a microscopic calculation, the scaling properties of entanglement in spin chain systems, both near and at a quantum critical point. Our results establish a precise connection between concepts of quantum information, condensed matter physics, and quantum field theory, by showing that the behavior of critical entanglement in spin systems is analogous to that of entropy in conformal field theories. We explore some of the implications of this connection.

J. Holland

Said S. Al-gahtani, Geoffrey S. Hubona, Jijie Wang

G. Hult, D. Ketchen, S. Slater

Gilles Pisier

Mathew L. A. Hayward, D. Shepherd, D. Griffin

Geoffrey Smith

Dejan Stančević, Luca Ambrogioni

Generative diffusion models have emerged as a powerful class of models in machine learning, yet a unified theoretical understanding of their operation is still developing. This paper provides an integrated perspective on generative diffusion by connecting the information-theoretic, dynamical, and thermodynamic aspects. We demonstrate that the rate of conditional entropy production during generation (i.e., the generative bandwidth) is directly governed by the expected divergence of the score function’s vector field. This divergence, in turn, is linked to the branching of trajectories and generative bifurcations, which we characterize as symmetry-breaking phase transitions in the energy landscape. Beyond ensemble averages, we demonstrate that symmetry-breaking decisions are revealed by peaks in the variance of pathwise conditional entropy, capturing heterogeneity in how individual trajectories resolve uncertainty. Together, these results establish generative diffusion as a process of controlled, noise-induced symmetry breaking, in which the score function acts as a dynamic nonlinear filter that regulates both the rate and variability of information flow from noise to data.

G. Gour, Markus P. Muller, Varun Narasimhachar et al.

We review recent work on the foundations of thermodynamics in the light of quantum information theory. We adopt a resource-theoretic perspective, wherein thermodynamics is formulated as a theory of what agents can achieve under a particular restriction, namely, that the only state preparations and transformations that they can implement for free are those that are thermal at some fixed temperature. States that are out of thermal equilibrium are the resources. We consider the special case of this theory wherein all systems have trivial Hamiltonians (that is, all of their energy levels are degenerate). In this case, the only free operations are those that add noise to the system (or implement a reversible evolution) and the only nonequilibrium states are states of informational nonequilibrium, that is, states that deviate from the maximally mixed state. The degree of this deviation we call the state’s nonuniformity; it is the resource of interest here, the fuel that is consumed, for instance, in an erasure operation. We consider the different types of state conversion: exact and approximate, single-shot and asymptotic, catalytic and noncatalytic. In each case, we present the necessary and sufficient conditions for the conversion to be possible for any pair of states, emphasizing a geometrical representation of the conditions in terms of Lorenz curves. We also review the problem of quantifying the nonuniformity of a state, in particular through the use of generalized entropies, and that of quantifying the gap between the nonuniformity one must expend to achieve a single-shot state preparation or state conversion and the nonuniformity one can extract in the reverse operation. Quantum state-conversion problems in this resource theory can be shown to be always reducible to their classical counterparts, so that there are no inherently quantum-mechanical features arising in such problems. This body of work also demonstrates that the standard formulation of the second law of thermodynamics is inadequate as a criterion for deciding whether or not a given state transition is possible.

V. V. Gerasimenko, K. V. Simonov

In pricing management the dominating approach is applied on the basis of the classical paradigm of negative correlation between demand and price, which leads to overenthusiastic preference of price sales incentives and discount-bonus programs. However, the actual results of retailing raise doubts about unwavering fairness of this rule and unconditional effectiveness of the corresponding activities. The reason for this presumably lies in irrational perception of prices bycustomers, which probably needs to use heuristic adjustments in price management to increase retail profits. the objectives of the study is to justify the need of combining two methodological approaches for Russian retailing system when managing pricing — formalized and heuristic — by means of modeling situations of consumer choice of retail purchase and analysis of its determinants. The methodological basis combines the conceptual provisions of economic theory, as well as the theory of consumer’s behavioral analysis. Research methods: in-depth interviews with management specialists and experts, who assessed scenario cases, as well as by means of contextual and narrative analyses. Information base of the study consists of modern scientific publications and practical analysis data obtained by means of 110 in-depth interviews conducted in the second half of 2023 and the first quarter of 2024. The research findings show that price management in retailing should take into account the impact of pluralistic nature of irrational price perception and spontaneous customer reactions to prices. Practical significance: this study may facilitate Russian retailers to forecast price reactions of customers and find effective prices; it will be helpful for teaching management disciplines, and may also be in demand in the process of integration of neoclassical and behavioral models in the context of retail pricing management.

Jan Mietzner, Cerikh Chakraborty, Peter A. Hoeher et al.

Talkative power conversion (TPC) is a switching ripple communication technique that integrates data modulation into a switched-mode power electronics converter, enabling simultaneous information transmission and power conversion. Despite numerous research papers published over the last decade on various theoretical and practical aspects of this emerging topic, thorough signal modeling suitable for analysis, computer simulations, and the development of suitable receiver architectures is still lacking. In this article, we derive the continuous-time output voltage of a DC/DC switched-mode power electronics converter for a broad range of pulsed-based modulation schemes. We also develop corresponding discrete-time signal models and assess their accuracies. Finally, we devise a generic end-to-end signal model for arbitrary modulation signals, discuss implications of continuous-time and discrete-time signal modeling on equalization, and consider generalizations to include parasitic effects as well as the influence of general impedance loads. This is the first time that comprehensive continuous- and discrete-time signal models are presented for TPC, including also general settings. In particular, the signal models take the initial values of all relevant variables into account and are therefore able to fully capture transient start-up behavior. Our signal modeling approach therefore provides a common framework for the fields of power electronics and communications engineering and can serve as a basis for system modeling regarding TPC system design, circuit design, evaluations, and optimizations.