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Entropy

Information and the Quantum World

Dennis Dieks

Published Jan 13, 2016• 9 citations
Publisher

Abstract

The concept of information is not different in quantum theory from its counterpart in classical physics: a sui generis quantum information concept is not needed. However, the quantum world is radically different from its classical counterpart. This difference in structure of the material world has important consequences for the amounts of information that can be stored in physical systems and for the possibilities of information transfer. In many cases, overlap between quantum states (non-orthogonality of states) blurs distinctions and impedes efficient information transfer. However, the other typical quantum feature, entanglement, makes new and seemingly mysterious ways of transporting information possible. In this article, we suggest an interpretational scheme of quantum mechanics in terms of perspectival physical properties that may provide an intelligible account of these novel quantum possibilities, while staying close to the mathematical formalism of quantum mechanics.

DOI
10.3390/e18010026

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Quantum Information and Locality

Dennis Dieks

The surprising aspects of quantum information are due to two distinctly non-classical features of the quantum world: first, different quantum states need not be orthogonal and, second, quantum states may be entangled. Non-orthogonality leads to the blurring of classical distinctions. On the other hand, entanglement leads via non-locality to teleportation and other ``entanglement-assisted'' forms of communication that go beyond what is classically possible. In this article we attempt to understand these new possibilities via an analysis of the significance of entanglement for the basic physical concepts of a ``particle'' and a ``localized physical system''. Classical particles can be individuated on the basis of qualitative differences in their sets of properties. But in entangled states the ``particle labels'' of the quantum formalism usually do not pick out such sets of individuating particle properties. It is sometimes nevertheless possible to think in terms of individual particles, which may be localized; but we argue that in general the structure of quantum mechanics is at odds with such a particle interpretation. This finally leads us to the conclusion that quantum mechanics is best seen as not belonging to the category of space-time theories, in which physical quantities are functions on space-time points. The resulting picture of the quantum world is relevant for our understanding of the way in which quantum theory is non-local, and it sheds light on the novel aspects of quantum information.

Cambridge University Press eBooks•Apr 24, 2017•5 citations

All the physical world as mathematical: Physical entity as quantum information

Vasil Dinev Penchev

Quantum mechanics was reformulated as an information theory involving a generalized kind of information, namely quantum information, in the end of the last century. Quantum mechanics is the most fundamental physical theory referring to all claiming to be physical. Any physical entity turns out to be quantum information in the final analysis. A quantum bit is the unit of quantum information, and it is a generalization of the unit of classical information, a bit, as well as the quantum information itself is a generalization of classical information. Classical information refers to finite series or sets while quantum information, to infinite ones. Quantum information as well as classical information is a dimensionless quantity. Quantum information can be considered as a “bridge” between the mathematical and physical. The standard and common scientific epistemology grants the gap between the mathematical models and physical reality. The conception of truth as adequacy is what is able to transfer “over” that gap. One should explain how quantum information being a continuous transition between the physical and mathematical may refer to truth as adequacy and thus to the usual scientific epistemology and methodology. If it is the overall substance of anything claiming to be physical, one can question how different and dimensional physical quantities appear. Quantum information can be discussed as the counterpart of action. Quantum information is what is conserved, action is what is changed in virtue of the fundamental theorems of Emmy Noether (1918). The gap between mathematical models and physical reality, needing truth as adequacy to be overcome, is substituted by the openness of choice. That openness in turn can be interpreted as the openness of the present as a different concept of truth recollecting Heidegger’s one as “unconcealment” (ἀλήθεια). Quantum information as what is conserved can be thought as the conservation of that openness

•May 31, 2020•0 citations

Elements of quantum theory

Stephen Mark Barnett

We have seen that there is an intimate relationship between probability and information. The values we assign to probabilities depend on the information available, and information is a function of probabilities. This connection makes it inevitable that information will be an important concept in any statistical theory, including thermodynamics and, of course, quantum physics. The probabilistic interpretation of quantum theory has probability amplitudes rather than probabilities as the fundamental quantities. This feature, together with the associated superposition principle, is responsible for intrinsically quantum phenomena and gives quantum information theory its distinctive flavour. We shall see that the quantum rules for dynamical evolution and measurement, together with the existence of entangled states, have important implications for quantum information. They also make it possible to perform tasks which are either impractical or impossible within the classical domain. In describing these we shall make extensive use of simple but fundamental ideas in quantum theory. This chapter introduces the mathematical description of quantum physics and the concepts which will be employed in our study of quantum information.

Oxford University Press eBooks•May 28, 2009•1 citation

Questioning of Quantum Information

WU Guo-lin

Introduction The quantum information theory began to rise in the end of 20th century. The EPR (relation)really is quantum entanglement, Consequently, it makes the concept of information in science expand from classical information theory to quantum information theory, and a new concept of quantum information formed. The primary concept of information faced to new challenges and produced some important philosophical questions. For example, can we set up the concept of quantum information? What is the nature of quantum information? The past common concept of information (the information is the elimination of uncertainty) could be used in quantum information? Whether does the emergence of quantum computation mean to eliminate no-boundaries between the quantum and the classical? My aim in this paper is to discuss these questions. My philosophical analysis focuses, however, on the basic quantum information theory. Methods The research method is analytical philosophy and logic that make quantum conception more clear and accurate. Results and Discussion The concept of information could be set up. fundamentally speaking, it did be supported by the Shannon information theory and further philosophical reflections. According of information theory, (classical) information concept could be set up, and there are two necessary preconditions: (a) the premise is a set of possible events, and they can be described by the probability. (b) the information is the elimination of uncertainty. Fundamentally, quantum information is also satisfied with the family-resemblance two preconditions: (1) Quantum information describes the possibility of microscopic things, and quantum information is the expression of wave function. The wave function describes the state of microscopic particles, and presentation of the possibility of microscopic objects. (2) On the aspect of eliminating the uncertainty, the quantum communication is same as classical communication. The signal receiver once received quantum signals transmitted, and the receiver eliminates the corresponding uncertainty of quantum. Therefore, the quantum information is the elimination of quantum uncertainty, and which is called quantum information I. From two point of views, the possible events and eliminate uncertainty, the quantum information and classical information have family resemblance. Quantum information like Classical information way of transmission, it is delivered by the information source, and is received by recipient through the information channel. Quantum Information is similar to classical information, but more essential difference between them, specifically in the following three aspects: (1) The probability directly describe the possibility of classic events, while wave function (or probability amplitude) describes quantum events in the quantum world, and the absolute square of wave function is corresponded to classical probability. (2)There have the essential difference between qubits (quantum qits) and classical bits. (3) Classical information can be completely cloned or deleted. nevertheless, quantum information is neither cloned (no-cloning), nor removed completely. To my point of view, through the analysis of the process of quantum teleportation, a quantum uncertainty can be divided into three categories: the first is the external uncertainties of microscopic particles; the second the uncertainty of the superposition state; the third the inherent uncertainty of microscopic particles. These three uncertainties can be eliminated by three different ways that are transmission of quantum information, accurate quantum transformations and the creations of quantum entanglement. Therefore we can give the general definition of certainty: a situation (the state of events, things) is of certainty, if they are satisfied with the following conditions: (a) a situation is entirely determined by n events parameters; (b) n parameters of events has an accurate values simultaneously. The existences of quantum states form quantum facts. Quantum states show themselves, and therefore it releases the information to the outside world. For this reason, there have two aspects of quantum state which need to express: existence of quantum state is the quantum fact, here we emphasize "existence"; and quantum state can show to the external world, which is the quantum information, here we emphasize "Show". Hence, quantum information is the show(Zeigt) of quantum state, which is called quantum information II. The nature of quantum information is the show of quantum events and their correlated ways. Quantum information is a kind of certainty and order. Quantum information can be divided into quantum informationⅠand quantum informationⅡ.. Quantum InformationⅠjust only a phenomenonal definition, it does not go deeply into the nature of the information. Therefore, the elimination of uncertainty can not be seen as the nature of quantum information itself . In the process of quantum teleportation, the source of quantum information (such as quantum state , a and b are coefficients) is delivered to the receiver, what is the essence of quantum information? From the point of view of quantum information theory, quantum state represents quantum information, quantum state is the state of quantum system (or microscopic particles) or quantum events. in the quantum state , what quantum states disclose the quantum information does not be the absolute size of quantum information, but the relationship, since the coefficients a and b satisfy the condition , and it do not be important numerical a and b, but between their relative size and relationship, which reflects the correlated ways between a and b. The connotation of quantum InformationⅠand quantum information Ⅱ offers support for the common view of classical information concept. Which is more deeply to disclose the nature of quantum information for both of them? Obviously, quantum information Ⅱ reflects the nature of quantum information. Quantum reality and quantum information are unified. What the wave function expresses is quantum reality. The wave function is unified of quantum information and quantum reality. There is no quantum reality, there is no quantum information. Because of the information and reality are unified, and quantum information different from classical information, so we can deduce that quantum reality is different from classical reality, and quantum computing differs from classical computing. In the classical parallel computing, the value calculated in different circuits respectively, but in parallel quantum computing the value calculated in one circuit, which is the essential difference between classical and quantum parallel computing. Many worlds interpretation of quantum mechanics does not mean that the difference between quantum and classical disappears: (1) Superposition in the microscopic world is very different from classical macroscopic physical world, so it is impossible that the superposition principle is fit for quantum world used for the classical world; (2) "To perform a quantum measurement, quantum world can be split up numerous classical world" is not supported by any experience and evidence; (3) Each branches of quantum computing are in quantum states, and quantum states are coherent, holistic, and some even entangled. Nevertheless, it is impossible for classical computing to achieve the quantum computing’s specific features; (4) The essential differences between quantum and the classical are decided by the development history of quantum mechanics and quantum information theory. The differences between quantum and the classical is really established by the quantum theory, concepts and their experiments that include Heisenberg’s matrix mechanics of Schrodinger’s wave equation, uncertainty principle of quantum mechanics and quantum entanglement phenomena and so on. They are completely different from the classical physical theories, concepts and experiments. Figure 1. Quantum information processing (see PDF version for the Figure). Conclusions This fruitful work gives an discussion of quantum concept that is the quantum information is the elimination of quantum uncertainty, which is called quantum information I and quantum information is the show (Zeigt) of quantum state, which is called quantum information II. Quantum information II reflects the nature of quantum information. The nature of quantum information is the show of quantum events and their correlated ways. Acknowledgments This research work of this paper is supported by 2011 the Philosophy and Social Sciences Foundation of the Ministry of Education of P. R. China (Project Number: 11JZD007) " Studies of the development trend of contemporary technological philosophy" . References and Notes Weiner, N., Cybernetics and Society. Houghton Mifflin Company, 1950. Shannon, C. E., The Mathematical Theory of Communication. The Bell System Technical Journal. 1948, Vol.27, pp.379-423, 623-656. Kornwachs K., Jacoby K., Introduction: What’s new about information? In Kornwachs K., Jacoby K.eds. Information. Berlin: Akademic Verlag GmbH. 1996. Bouwmeester, D. Pan, J.-W.,et al. Experimental Quantum Teleportation. Nature. 1997. 390. Bennett C. H. and Di Vinecenzo D. P. quantum information and computation, Nature, 2000, 404. Einstein, A. Podolsky B., and Rosen, N. Can Quantum-Mechanical Description of Physical Reality Be Considered Complete? Physical Review. 1935,47. Nielsen, M. A. Chuang, I. L., Quantum Computation and Quantum Information. Cambridge University Press, 2000. Duwell, A. Quantum information does not exist. Studies in History and Philosophy of Modern Physics,2003, (34). Berta, M. Christandl, M. Colbeck, R., et al. The uncertainty principle in the presence of quantum memory. Nat. Phys., 2010, (6). Caves, M. and Fuchs,C. A. 1996. Quantum information:how much information in a state vector?. preprint quant-ph/9601025. Barrow, J., et al, Science and Ultimate Reality: Quantum Theory, Cosmology and Complexity. Cambridge University Press. 2004. Yongde Zhang, Principles of Quantum Information Physics. Beijing: Science Press. 2006. Wheeler, J. A., At Home in the Universe. New York: Springer-Verlag. 1996. Guolin Wu, Quantum Entanglement And Its Philosophical Meaning, Studies in Dialectics of Nature, 2005, (7). Guolin Wu, A Detailed Philosophical Inquiry of the Quantum Information, Philosophical Researches. 2014, (8). Guolin Wu, Philosophical Connotation of quantum information Technology. Philosophical Trend. 2013, (8).

ISIS Summit: The Information Society at the Crossroads•Jun 19, 2015•0 citations

The Physics of Information

Torsten A. Enßlin, Jens Jasche, John Skilling

What is information? A short answer could be: Anything that changes our minds and states of thinking! Information is virtual. It can be carried by speech, an image, scratches on a stone, patterns in a photon field, the connections of neurons in our brains or even by the wavefunction of an electron. Information does not depend on the actual means of transmission nor does its identity change when changing the carrier. Information is physical. It needs to be sustained by a physical substrate and rearranging that substrate to contain the wanted information requires to spend energy or work. Without a physical world, information can not be stored, processed, or transmitted. Our world is permeated with different representations of information. Actually Information about the physical laws governing our Universe can be found everywhere and in everything. Could it then be that the real fundamental elements of this world are tiny bits of information? Could we get it from bit?1 A number of researcher investigate this possibility, and several of their attempts to recover physical laws from the principles governing information are reported about in this special issue on physics of information. The articles by Gregg Jaeger,2 by Ariel Caticha,3 and by John Skilling and Kevin Knuth4 address the reconstruction of quantum mechanics from information theory. Furthermore, Kevin Knuth and James Walsh5 show how to recover space-time from particles sending each others signals in an initially geometry-free setting. A central element of most works on information is the concept of a probability. Probabilities can be defined via various routes. Most familiar might be their definitions by the frequentists school as relative frequencies of events (in the limit of infinite amounts of such). A more general definition of probabilities is the Bayesians' one, which regards probabilities as quantifiers of statements, expressing how much those should be expected to be true. Although this definition looks subjective on the first glance, it rests on a solid mathematical theorem by Richard Cox6 that any extension of binary logic to a continuum of single valued truthfulness quantifier that respects a minimum of requirements must be isomorphic to probability theory. And this definition turns out to embrace the frequentists' definition in case that infinite numbers of comparable events are actually available and can be counted. The majority of authors of this special issues seem to favor the Bayesian perspective, which is probably a result of our own, the guest editors', preference and not necessarily a reflection of the prevailing position of contemporary scientists. The different views on probabilities of frequentists and Bayesians are addressed by the article of Allen Caldwell.7 He builds a bridge between these antagonistic camps by explaining frequentists' constructions in a Bayesian language. In particular, his argumentation why the omnipresent p-value in statistical and experimental literature might often capture a relevant signal of model misfit is reassuring, given that a large fraction of our medical system is based on decisions backed up by p-values. A Bayesian might add that it would be even more reassuring, if a system rigorously build on logic and its continuous extension would be used for decisions affecting live-or-death questions. The laws governing probabilities themselves seem to reflect that of more elementary mathematical structures. Kevin Knuth shows how these emerge from lattice theory, which deals with relations in partially ordered sets like that of collections of possibilities.8 The sum rule of probability theory is a direct consequence of the underlying lattice structure. Interestingly, a number of other theories are resting also on such lattices and therefore exhibit their own versions of sum rules: measures of sets, mutual information, the Euler characteristics of topological spaces, as well as quantum mechanical interactions that are quantified by pairs of numbers, the real and imaginary parts of complex probability amplitudes (see also4). The theory of information has very practical application in physics and elsewhere. Manfred Opper discusses how the solutions of stochastic differential equations can be inferred via variational methods, which have their origin in thermodynamics.9 Torsten Enßlin introduces information field theory (IFT), the information theory for fields, as a means to infer the configuration of a physical field from incomplete and noisy data.10 The mathematical apparatus for this is that of quantum field theory (QFT), just with ordinary probabilities instead of complex probability amplitudes as in the latter. Could it be that the difference between IFT and QFT is just be the same as between classical information theory and quantum mechanics, the transition from real valued to complex valued quantifier for statements? Anyhow, any practical inference machinery, be it for dynamical systems or for fields, requires sophisticated numerical methods. Michael Betancourt reviews Markov Chain Monte Carlo Methods to calculate expectation values over high dimensional probabilities.11 Theo Steininger and coworkers present the NIFTy3 software package for numerical information field theory calculations, which can handle very high dimensional field inference problems.12 Finally, in an article focused on the subtleties of the Monty Hall problem and mostly aiming at information theoretical entertainment, Torsten Enßlin and Margret Westercamp investigate the possibility that human intuition might be more rational than contemporary psychology thinks.13 A number of possible topics for an issue on physics of information are not addressed here. We would have loved to have articles on Landauer's principle, which states that erasing information has to cost energy, on QBism, a Bayesian version of quantum mechanics, on artificial and biological neural networks, as well as any other aspect of the information-soaked biological world. What has a reader of this special issue to be equipped with in order to follow the lines of thoughts? In addition to the usual physicist's education, the minimal additional equipment are the basics of probability theory and the concept of entropy. Most of the other concepts used in the articles rest on those and are introduced there. Let A, B, and C be propositions (or possibilities). The probability P ( A | B ) of A being true assuming that B is true is a number between 0 and 1, with P ( A | B ) = 1 expressing certainty of A under B ( B ⇒ A ) and P ( A | B ) = 0 expressing certainty of not A being the case under B ( B ⇒ ¬ A ).

Annalen der Physik•Mar 1, 2019•3 citations

The union of physics and information

Igor Devetak, Anne Staples

A union of quantum mechanics, thermodynamics and information theory is presented. It is accomplished by reinterpreting the mathematical formalism of Everett’s many-worlds theory of quantum mechanics and augmenting it to include preparation according to a given ensemble. The notion of directed entanglement is introduced through which both classical and quantum communication over quantum channels are reduced to entanglement transfer. The paradox of constant thermodynamic entropy in a closed quantum system is resolved. The view taken in this Letter is that the totality of conceptual experience can be described in terms of correlated random variables. This will allow us to make contact with Shannon’s information theory [1] in which random variables are the carriers of information. Two protagonists sharing the same physical world is no more than classical correlations between the states of their knowledge regarding that world. Similarly, the observation of definite physical laws is no more than classical correlations between states of knowledge regarding two consecutive acts of measurement, or preparation and measurement, depending on the experiment. For instance, a ball kicked by Alice seen as obeying Newton’s deterministic laws of motion is merely a statement about the correlation

•Jan 1, 2002•1 citation
The concept of information is not different in quantum theory from its counterpart in classical physics: a sui generis quantum information concept is not needed. However, the quantum world is radically different from its classical counterpart. This difference in structure of the material world has important consequences for the amounts of information that can be stored in physical systems and for the possibilities of information transfer. In many cases, overlap between quantum states (non-orthogonality of states) blurs distinctions and impedes efficient information transfer. However, the other typical quantum feature, entanglement, makes new and seemingly mysterious ways of transporting information possible. In this article, we suggest an interpretational scheme of quantum mechanics in terms of perspectival physical properties that may provide an intelligible account of these novel quantum possibilities, while staying close to the mathematical formalism of quantum mechanics.
The surprising aspects of quantum information are due to two distinctly non-classical features of the quantum world: first, different quantum states need not be orthogonal and, second, quantum states may be entangled. Non-orthogonality leads to the blurring of classical distinctions. On the other hand, entanglement leads via non-locality to teleportation and other ``entanglement-assisted'' forms of communication that go beyond what is classically possible. In this article we attempt to understand these new possibilities via an analysis of the significance of entanglement for the basic physical concepts of a ``particle'' and a ``localized physical system''. Classical particles can be individuated on the basis of qualitative differences in their sets of properties. But in entangled states the ``particle labels'' of the quantum formalism usually do not pick out such sets of individuating particle properties. It is sometimes nevertheless possible to think in terms of individual particles, which may be localized; but we argue that in general the structure of quantum mechanics is at odds with such a particle interpretation. This finally leads us to the conclusion that quantum mechanics is best seen as not belonging to the category of space-time theories, in which physical quantities are functions on space-time points. The resulting picture of the quantum world is relevant for our understanding of the way in which quantum theory is non-local, and it sheds light on the novel aspects of quantum information.
Quantum mechanics was reformulated as an information theory involving a generalized kind of information, namely quantum information, in the end of the last century. Quantum mechanics is the most fundamental physical theory referring to all claiming to be physical. Any physical entity turns out to be quantum information in the final analysis. A quantum bit is the unit of quantum information, and it is a generalization of the unit of classical information, a bit, as well as the quantum information itself is a generalization of classical information. Classical information refers to finite series or sets while quantum information, to infinite ones. Quantum information as well as classical information is a dimensionless quantity. Quantum information can be considered as a “bridge” between the mathematical and physical. The standard and common scientific epistemology grants the gap between the mathematical models and physical reality. The conception of truth as adequacy is what is able to transfer “over” that gap. One should explain how quantum information being a continuous transition between the physical and mathematical may refer to truth as adequacy and thus to the usual scientific epistemology and methodology. If it is the overall substance of anything claiming to be physical, one can question how different and dimensional physical quantities appear. Quantum information can be discussed as the counterpart of action. Quantum information is what is conserved, action is what is changed in virtue of the fundamental theorems of Emmy Noether (1918). The gap between mathematical models and physical reality, needing truth as adequacy to be overcome, is substituted by the openness of choice. That openness in turn can be interpreted as the openness of the present as a different concept of truth recollecting Heidegger’s one as “unconcealment” (ἀλήθεια). Quantum information as what is conserved can be thought as the conservation of that openness
We have seen that there is an intimate relationship between probability and information. The values we assign to probabilities depend on the information available, and information is a function of probabilities. This connection makes it inevitable that information will be an important concept in any statistical theory, including thermodynamics and, of course, quantum physics. The probabilistic interpretation of quantum theory has probability amplitudes rather than probabilities as the fundamental quantities. This feature, together with the associated superposition principle, is responsible for intrinsically quantum phenomena and gives quantum information theory its distinctive flavour. We shall see that the quantum rules for dynamical evolution and measurement, together with the existence of entangled states, have important implications for quantum information. They also make it possible to perform tasks which are either impractical or impossible within the classical domain. In describing these we shall make extensive use of simple but fundamental ideas in quantum theory. This chapter introduces the mathematical description of quantum physics and the concepts which will be employed in our study of quantum information.
Introduction The quantum information theory began to rise in the end of 20th century. The EPR (relation)really is quantum entanglement, Consequently, it makes the concept of information in science expand from classical information theory to quantum information theory, and a new concept of quantum information formed. The primary concept of information faced to new challenges and produced some important philosophical questions. For example, can we set up the concept of quantum information? What is the nature of quantum information? The past common concept of information (the information is the elimination of uncertainty) could be used in quantum information? Whether does the emergence of quantum computation mean to eliminate no-boundaries between the quantum and the classical? My aim in this paper is to discuss these questions. My philosophical analysis focuses, however, on the basic quantum information theory. Methods The research method is analytical philosophy and logic that make quantum conception more clear and accurate. Results and Discussion The concept of information could be set up. fundamentally speaking, it did be supported by the Shannon information theory and further philosophical reflections. According of information theory, (classical) information concept could be set up, and there are two necessary preconditions: (a) the premise is a set of possible events, and they can be described by the probability. (b) the information is the elimination of uncertainty. Fundamentally, quantum information is also satisfied with the family-resemblance two preconditions: (1) Quantum information describes the possibility of microscopic things, and quantum information is the expression of wave function. The wave function describes the state of microscopic particles, and presentation of the possibility of microscopic objects. (2) On the aspect of eliminating the uncertainty, the quantum communication is same as classical communication. The signal receiver once received quantum signals transmitted, and the receiver eliminates the corresponding uncertainty of quantum. Therefore, the quantum information is the elimination of quantum uncertainty, and which is called quantum information I. From two point of views, the possible events and eliminate uncertainty, the quantum information and classical information have family resemblance. Quantum information like Classical information way of transmission, it is delivered by the information source, and is received by recipient through the information channel. Quantum Information is similar to classical information, but more essential difference between them, specifically in the following three aspects: (1) The probability directly describe the possibility of classic events, while wave function (or probability amplitude) describes quantum events in the quantum world, and the absolute square of wave function is corresponded to classical probability. (2)There have the essential difference between qubits (quantum qits) and classical bits. (3) Classical information can be completely cloned or deleted. nevertheless, quantum information is neither cloned (no-cloning), nor removed completely. To my point of view, through the analysis of the process of quantum teleportation, a quantum uncertainty can be divided into three categories: the first is the external uncertainties of microscopic particles; the second the uncertainty of the superposition state; the third the inherent uncertainty of microscopic particles. These three uncertainties can be eliminated by three different ways that are transmission of quantum information, accurate quantum transformations and the creations of quantum entanglement. Therefore we can give the general definition of certainty: a situation (the state of events, things) is of certainty, if they are satisfied with the following conditions: (a) a situation is entirely determined by n events parameters; (b) n parameters of events has an accurate values simultaneously. The existences of quantum states form quantum facts. Quantum states show themselves, and therefore it releases the information to the outside world. For this reason, there have two aspects of quantum state which need to express: existence of quantum state is the quantum fact, here we emphasize "existence"; and quantum state can show to the external world, which is the quantum information, here we emphasize "Show". Hence, quantum information is the show(Zeigt) of quantum state, which is called quantum information II. The nature of quantum information is the show of quantum events and their correlated ways. Quantum information is a kind of certainty and order. Quantum information can be divided into quantum informationⅠand quantum informationⅡ.. Quantum InformationⅠjust only a phenomenonal definition, it does not go deeply into the nature of the information. Therefore, the elimination of uncertainty can not be seen as the nature of quantum information itself . In the process of quantum teleportation, the source of quantum information (such as quantum state , a and b are coefficients) is delivered to the receiver, what is the essence of quantum information? From the point of view of quantum information theory, quantum state represents quantum information, quantum state is the state of quantum system (or microscopic particles) or quantum events. in the quantum state , what quantum states disclose the quantum information does not be the absolute size of quantum information, but the relationship, since the coefficients a and b satisfy the condition , and it do not be important numerical a and b, but between their relative size and relationship, which reflects the correlated ways between a and b. The connotation of quantum InformationⅠand quantum information Ⅱ offers support for the common view of classical information concept. Which is more deeply to disclose the nature of quantum information for both of them? Obviously, quantum information Ⅱ reflects the nature of quantum information. Quantum reality and quantum information are unified. What the wave function expresses is quantum reality. The wave function is unified of quantum information and quantum reality. There is no quantum reality, there is no quantum information. Because of the information and reality are unified, and quantum information different from classical information, so we can deduce that quantum reality is different from classical reality, and quantum computing differs from classical computing. In the classical parallel computing, the value calculated in different circuits respectively, but in parallel quantum computing the value calculated in one circuit, which is the essential difference between classical and quantum parallel computing. Many worlds interpretation of quantum mechanics does not mean that the difference between quantum and classical disappears: (1) Superposition in the microscopic world is very different from classical macroscopic physical world, so it is impossible that the superposition principle is fit for quantum world used for the classical world; (2) "To perform a quantum measurement, quantum world can be split up numerous classical world" is not supported by any experience and evidence; (3) Each branches of quantum computing are in quantum states, and quantum states are coherent, holistic, and some even entangled. Nevertheless, it is impossible for classical computing to achieve the quantum computing’s specific features; (4) The essential differences between quantum and the classical are decided by the development history of quantum mechanics and quantum information theory. The differences between quantum and the classical is really established by the quantum theory, concepts and their experiments that include Heisenberg’s matrix mechanics of Schrodinger’s wave equation, uncertainty principle of quantum mechanics and quantum entanglement phenomena and so on. They are completely different from the classical physical theories, concepts and experiments. Figure 1. Quantum information processing (see PDF version for the Figure). Conclusions This fruitful work gives an discussion of quantum concept that is the quantum information is the elimination of quantum uncertainty, which is called quantum information I and quantum information is the show (Zeigt) of quantum state, which is called quantum information II. Quantum information II reflects the nature of quantum information. The nature of quantum information is the show of quantum events and their correlated ways. Acknowledgments This research work of this paper is supported by 2011 the Philosophy and Social Sciences Foundation of the Ministry of Education of P. R. China (Project Number: 11JZD007) " Studies of the development trend of contemporary technological philosophy" . References and Notes Weiner, N., Cybernetics and Society. Houghton Mifflin Company, 1950. Shannon, C. E., The Mathematical Theory of Communication. The Bell System Technical Journal. 1948, Vol.27, pp.379-423, 623-656. Kornwachs K., Jacoby K., Introduction: What’s new about information? In Kornwachs K., Jacoby K.eds. Information. Berlin: Akademic Verlag GmbH. 1996. Bouwmeester, D. Pan, J.-W.,et al. Experimental Quantum Teleportation. Nature. 1997. 390. Bennett C. H. and Di Vinecenzo D. P. quantum information and computation, Nature, 2000, 404. Einstein, A. Podolsky B., and Rosen, N. Can Quantum-Mechanical Description of Physical Reality Be Considered Complete? Physical Review. 1935,47. Nielsen, M. A. Chuang, I. L., Quantum Computation and Quantum Information. Cambridge University Press, 2000. Duwell, A. Quantum information does not exist. Studies in History and Philosophy of Modern Physics,2003, (34). Berta, M. Christandl, M. Colbeck, R., et al. The uncertainty principle in the presence of quantum memory. Nat. Phys., 2010, (6). Caves, M. and Fuchs,C. A. 1996. Quantum information:how much information in a state vector?. preprint quant-ph/9601025. Barrow, J., et al, Science and Ultimate Reality: Quantum Theory, Cosmology and Complexity. Cambridge University Press. 2004. Yongde Zhang, Principles of Quantum Information Physics. Beijing: Science Press. 2006. Wheeler, J. A., At Home in the Universe. New York: Springer-Verlag. 1996. Guolin Wu, Quantum Entanglement And Its Philosophical Meaning, Studies in Dialectics of Nature, 2005, (7). Guolin Wu, A Detailed Philosophical Inquiry of the Quantum Information, Philosophical Researches. 2014, (8). Guolin Wu, Philosophical Connotation of quantum information Technology. Philosophical Trend. 2013, (8).
What is information? A short answer could be: Anything that changes our minds and states of thinking! Information is virtual. It can be carried by speech, an image, scratches on a stone, patterns in a photon field, the connections of neurons in our brains or even by the wavefunction of an electron. Information does not depend on the actual means of transmission nor does its identity change when changing the carrier. Information is physical. It needs to be sustained by a physical substrate and rearranging that substrate to contain the wanted information requires to spend energy or work. Without a physical world, information can not be stored, processed, or transmitted. Our world is permeated with different representations of information. Actually Information about the physical laws governing our Universe can be found everywhere and in everything. Could it then be that the real fundamental elements of this world are tiny bits of information? Could we get it from bit?1 A number of researcher investigate this possibility, and several of their attempts to recover physical laws from the principles governing information are reported about in this special issue on physics of information. The articles by Gregg Jaeger,2 by Ariel Caticha,3 and by John Skilling and Kevin Knuth4 address the reconstruction of quantum mechanics from information theory. Furthermore, Kevin Knuth and James Walsh5 show how to recover space-time from particles sending each others signals in an initially geometry-free setting. A central element of most works on information is the concept of a probability. Probabilities can be defined via various routes. Most familiar might be their definitions by the frequentists school as relative frequencies of events (in the limit of infinite amounts of such). A more general definition of probabilities is the Bayesians' one, which regards probabilities as quantifiers of statements, expressing how much those should be expected to be true. Although this definition looks subjective on the first glance, it rests on a solid mathematical theorem by Richard Cox6 that any extension of binary logic to a continuum of single valued truthfulness quantifier that respects a minimum of requirements must be isomorphic to probability theory. And this definition turns out to embrace the frequentists' definition in case that infinite numbers of comparable events are actually available and can be counted. The majority of authors of this special issues seem to favor the Bayesian perspective, which is probably a result of our own, the guest editors', preference and not necessarily a reflection of the prevailing position of contemporary scientists. The different views on probabilities of frequentists and Bayesians are addressed by the article of Allen Caldwell.7 He builds a bridge between these antagonistic camps by explaining frequentists' constructions in a Bayesian language. In particular, his argumentation why the omnipresent p-value in statistical and experimental literature might often capture a relevant signal of model misfit is reassuring, given that a large fraction of our medical system is based on decisions backed up by p-values. A Bayesian might add that it would be even more reassuring, if a system rigorously build on logic and its continuous extension would be used for decisions affecting live-or-death questions. The laws governing probabilities themselves seem to reflect that of more elementary mathematical structures. Kevin Knuth shows how these emerge from lattice theory, which deals with relations in partially ordered sets like that of collections of possibilities.8 The sum rule of probability theory is a direct consequence of the underlying lattice structure. Interestingly, a number of other theories are resting also on such lattices and therefore exhibit their own versions of sum rules: measures of sets, mutual information, the Euler characteristics of topological spaces, as well as quantum mechanical interactions that are quantified by pairs of numbers, the real and imaginary parts of complex probability amplitudes (see also4). The theory of information has very practical application in physics and elsewhere. Manfred Opper discusses how the solutions of stochastic differential equations can be inferred via variational methods, which have their origin in thermodynamics.9 Torsten Enßlin introduces information field theory (IFT), the information theory for fields, as a means to infer the configuration of a physical field from incomplete and noisy data.10 The mathematical apparatus for this is that of quantum field theory (QFT), just with ordinary probabilities instead of complex probability amplitudes as in the latter. Could it be that the difference between IFT and QFT is just be the same as between classical information theory and quantum mechanics, the transition from real valued to complex valued quantifier for statements? Anyhow, any practical inference machinery, be it for dynamical systems or for fields, requires sophisticated numerical methods. Michael Betancourt reviews Markov Chain Monte Carlo Methods to calculate expectation values over high dimensional probabilities.11 Theo Steininger and coworkers present the NIFTy3 software package for numerical information field theory calculations, which can handle very high dimensional field inference problems.12 Finally, in an article focused on the subtleties of the Monty Hall problem and mostly aiming at information theoretical entertainment, Torsten Enßlin and Margret Westercamp investigate the possibility that human intuition might be more rational than contemporary psychology thinks.13 A number of possible topics for an issue on physics of information are not addressed here. We would have loved to have articles on Landauer's principle, which states that erasing information has to cost energy, on QBism, a Bayesian version of quantum mechanics, on artificial and biological neural networks, as well as any other aspect of the information-soaked biological world. What has a reader of this special issue to be equipped with in order to follow the lines of thoughts? In addition to the usual physicist's education, the minimal additional equipment are the basics of probability theory and the concept of entropy. Most of the other concepts used in the articles rest on those and are introduced there. Let A, B, and C be propositions (or possibilities). The probability P ( A | B ) of A being true assuming that B is true is a number between 0 and 1, with P ( A | B ) = 1 expressing certainty of A under B ( B ⇒ A ) and P ( A | B ) = 0 expressing certainty of not A being the case under B ( B ⇒ ¬ A ).
A union of quantum mechanics, thermodynamics and information theory is presented. It is accomplished by reinterpreting the mathematical formalism of Everett’s many-worlds theory of quantum mechanics and augmenting it to include preparation according to a given ensemble. The notion of directed entanglement is introduced through which both classical and quantum communication over quantum channels are reduced to entanglement transfer. The paradox of constant thermodynamic entropy in a closed quantum system is resolved. The view taken in this Letter is that the totality of conceptual experience can be described in terms of correlated random variables. This will allow us to make contact with Shannon’s information theory [1] in which random variables are the carriers of information. Two protagonists sharing the same physical world is no more than classical correlations between the states of their knowledge regarding that world. Similarly, the observation of definite physical laws is no more than classical correlations between states of knowledge regarding two consecutive acts of measurement, or preparation and measurement, depending on the experiment. For instance, a ball kicked by Alice seen as obeying Newton’s deterministic laws of motion is merely a statement about the correlation