Coherent information

About: Coherent information is a research topic. Over the lifetime, 1225 publications have been published within this topic receiving 46672 citations.

Quantum coherence induces pulse shape modification in a semiconductor optical amplifier at room temperature

Abstract: Coherence in light-matter interaction is a necessary ingredient if light is used to control the quantum state of a material system. Coherent effects are firmly associated with isolated systems kept at low temperature. The exceedingly fast dephasing in condensed matter environments, in particular at elevated temperatures, may well erase all coherent information in the material at timescales shorter than a laser excitation pulse. Here we show for an ensemble of semiconductor quantum dots that even in the presence of ultrafast dephasing, for suitably designed condensed matter systems quantum-coherent effects are robust enough to be observable at room temperature. Our conclusions are based on an analysis of the reshaping an ultrafast laser pulse undergoes on propagation through a semiconductor quantum dot amplifier. We show that this pulse modification contains the signature of coherent light-matter interaction and can be controlled by adjusting the population of the quantum dots via electrical injection.

The structure of physics

Abstract: Preface by the Editors Preface 1985 On Weizsacker's Philosophy of Physics (by H. Lyre) Chapter 1: Introduction. 1.1. The Question. 1.2. Outline Part I: The Unity of Physics Chapter 2: The System of theories. 2.1. Preliminary. 2.2. Classical point mechanics. 2.3. Mathematical forms of the Laws of Nature. 2.4. Chemistry. 2.5. Thermodynamics. 2.6. Field theories. 2.7. Non-Euclidan geometry and semantical consistency. 2.8. The relativity problem. 2.9. Special theory of relativity. 2.10. General theory of relativity. 2.11. Quantum theory, historical. 2.12. Quantum theory, plan of reconstruction. Chapter 3: Probability and abstract quantum theory. 3.1. Probability and experience. 3.2. The classical concept of probability. 3.3. Empirical determination of probabilities. 3.4. Second quantization. 3.5. Methodical: reconstruction of abstract quantum theory. 3.6. Reconstruction via probabilities and the lattice of propositions. Chapter 4: Quantum theory and space-time. 4.1. Concrete quantum theory. 4.2. Reconstruction of quantum theory via variable alternatives. 4.3. Space and time. Chapter 5: Models of particles and interaction. 5.1. Open questions. 5.2. Representations in tensor space. 5.3. Quasi-particles in rigid coordinate spaces. 5.4. Model of quantum electrodynamics. 5.5. Elementary particles. 5.6. General theory of relativity. Chapter 6: Cosmology and particle physics (by Th. Gornitz). 6.1. Quantum theory of abstract binary alternatives and cosmology. 6.2. Ur-theoretical vacuum and particle states. 6.4. Outlook. Part II: Time and Information Chapter 7: Irreversibility and entropy. 7.1. Irreversibility as problem. 7.2. A model of irreversible processes. 7.3. Documents. 7.4. Cosmology and the theory of relativity. Chapter 8: Information and evolution. 8.1. The systematic place of the chapter. 8.2. What is information? 8.3. What is evolution? 8.4. Information and probability. 8.5. Evolution as growth of potential information. 8.6. Pragmaticinformation: novelty and confirmation. 8.7. Biological preliminaries to logic. Part III: On the Interpretation of Physics Chapter 9: The problem of the interpretation of quantum theory. 9.1. About the history of the interpretation. 9.2. The semantical consistency of quantum theory. 9.3. Paradoxa and alternatives. Chapter 10: The stream of information. 10.1. The quest for substance. 10.2. The stream of information in quantum theory. 10.3. Mind and form. Chapter 11: Beyond quantum theory. 11.1. Crossing the frontier. 11.2. Facticity of the future. 11.3. Possibility of the past. 11.4. Comprehensive present. 11.5. Beyond physics. Chapter 12: In the language of philosophers. 12.1. Exposition. 12.2. Philosophy of science. 12.3. Physics. 12.4. Metaphysics. References Index

Quantum skew divergence

Abstract: In this paper, we study the quantum generalisation of the skew divergence, which is a dissimilarity measure between distributions introduced by Lee in the context of natural language processing. We provide an in-depth study of the quantum skew divergence, including its relation to other state distinguishability measures. Finally, we present a number of important applications: new continuity inequalities for the quantum Jensen-Shannon divergence and the Holevo information, and a new and short proof of Bravyi's Small Incremental Mixing conjecture.

Hypersensitivity to perturbation in the quantum kicked top.

Abstract: For the quantum kicked top we study numerically the distribution of Hilbert-space vectors evolving in the presence of a small random perturbation. For an initial coherent state centered in a chaotic region of the classical dynamics, the evolved perturbed vectors are distributed essentially like random vectors in Hilbert space. In contrast, for an initial coherent state centered near an elliptic (regular) fixed point of the classical dynamics, the evolved perturbed vectors remain close together, explore only a few dimensions of Hilbert space, and do not explore them randomly. These results support and extend the results of earlier studies, thereby providing additional support for a characterization of quantum chaos that uses concepts from information theory.

The next stage: quantum game theory

Abstract: Recent development in quantum computation and quantum information theory allows to extend the scope of game theory for the quantum world The paper presents the history, basic ideas and recent development in quantum game theory On grounds of the discussed material, we reason about possible future development of quantum game theory and its impact on information processing and the emerging information society