Quantum darwinism

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The Quantum Darwinism is a theory that describes a rating based on Darwinian selection emergence of the classical world of the quantum world. It was proposed jointly by Wojciech Zurek and a research group whose members include Ollivier, Poulin, Paz and Blume-Kohout, but its development goes back to the networking of some research areas carried out by Zurek. The following aspects are the main ones:

  • the evolution theory formulated by Darwin as a generally applicable algorithm
  • the so-called pointer states ( pointer states ) that are robust in their environment (not smudge ) and u in the form. a. inherit their content of information from the quantum into the world of classical physics
  • the theory of decoherence
  • and einselection ( " e nvironment- in duced super selection ") in which the environment is considered as a factor that exerts a selective pressure on the integral states.

Zurek has been researching this for around 25 years.

Effects

Similar to Zurek's theory of envariance (from " en tanglement-assisted in variance ", i.e. invariance supported by quantum entanglement), quantum Darwinism explains how the classical world emerges from the quantum world and offers possible solutions for the so-called measurement problem , the interpretation of which is philosophical represents the greatest challenge in the field of quantum theory. This problem arises because the vector of the quantum state (the source of all information about a quantum system) develops into a linear superposition according to the Schrödinger equation . This means that superimposed states such as B. "Schrödinger 's dead and alive cat " meant - situations that do not exist in our classical world. Various high-ranking quantum physicists often declare this problem to be solved (or nonexistent) by assuming that the state vector is transformed into the definitely measured state in a non-unitary way as a result of the measurement act .

The physical character of the transition from the superposition of states to the unambiguous classical state is usually not explained in today's quantum theory, but treated like an axiom ; Before that, it was the basis for the struggle for completeness of quantum theory between Niels Bohr and Albert Einstein - probably the most famous in the history of physics.

Quantum Darwinism describes the transition of every conceivable quantum system with its huge potential for variations to the very limited number of pointer states as a so-called single - selective process. The quantum system in question reacts in a way that adapts to its environment. All quantum interactions, typically with the ocean of photons omnipresent in the cosmos, but also e.g. B. a measuring apparatus lead to a quantum decoherence or manifestation of the quantum system in a certain basis of eigenstates, which are conditioned by the nature of the interaction in which the quantum system is involved. Zurek and his colleagues have now shown that these pointer states are the preferred result of the decoherence processes and are the basis of the classical states. In this way, the pointer states become areas of classical reality that are subject to further evolution.

Insofar as each quantum system consists of more or less redundant variations of the finally selected pointer states and these in turn represent information , the environment can be understood as a collection of observers who agree on a pointer state at the moment of decoherence (prefer it to the remaining variants). This aspect of Einselection , which Zurek calls the "Environment as Witness", potentially leads to objective knowledge . This is e.g. This is the case, for example, as soon as the primordial cosmic environment evolved (via a series of causally connected steps) into a scientist who knows how to verify his hypothesis and thereby convert it into a theory .

The importance of Darwinism

The theory of quantum Darwinism implies the assumption of a selective mechanism that creates our classical reality. As numerous scientists have made clear, every kind of natural selection leads to development (evolution), in the sense that a certain one begins to consolidate out of a set of earlier states, which assert itself alongside its 'ancestors' or also replace them (displace them) can. The special thing about Darwin's theory is that he did not restrict it to biology because of the logical origin of its hypothetical primordial unicellular cell from the realm of inanimate matter. In order to do justice to the claim to be able to explain the origin of the 'living' matter from the 'dead', he formulated the basic rules of the theory of evolution as simple, generally applicable algorithms :

  1. Reproduction - the ability to make copies of yourself and thus produce descendants.
  2. Inheritance - the fact that the copies created have "properties" (information).
  3. Variability - Differences between inherited traits result in different degrees of adaptation to the environment ("fitness"), which in turn reduces or increases the ability to survive and reproduce.

Quantum Darwinism seems to follow these algorithms, so its name is aptly chosen:

  1. Every quantum system contains potentially infinitely many copies (possible realities) that differ from each other more or less.
  2. The pointer states that have become reality as a result of the decoherence are carriers of properties (information), including the ability to pass them on to subsequent states.
  3. Successive interactions between pointer states and their environment show that they are particularly stable in relation to it and therefore rather "survive" (than countless other options of a quantum system) and develop further.

From this perspective, Zurek and colleagues offer a Darwinian explanation of the origin of our macroscopic reality from the quantum world. It is perhaps surprising that, according to a scientific theory, one and the same mechanism enables the emergence of the human spirit and its cultural achievements from biology and this from the enigmatic quantum reality.

literature

  • S. Haroche, J.-M. Raimond, Exploring the Quantum: Atoms, Cavities, and Photons , Oxford University Press (2006), ISBN 0-198-50914-6 , pp. 77 ff.
  • M. Schlosshauer, Decoherence and the Quantum-to-Classical Transition , Springer 2007, ISBN 3-540-35773-4 , chap. 2.9, p. 85 ff.

Web links

Original papers and documents

  • W. Zurek, Quantum Darwinism , Nature Physics 5 (2009) pp. 181-188 ( doi : 10.1038 / nphys1202 ).
  • R. Blume-Kohout, WH Zurek, Quantum Darwinism: Entanglement, branches, and the emergent classicality of redundantly stored quantum information , Phys. Rev. A 73, 062310 (2006). arxiv : quant-ph / 0505031 .
  • Zurek Quantum Darwinism and Envariance , 2003, arxiv : quant-ph / 0308163 .
  • Ollivier, Poulin, Zurek Environment as a Witness: Selective Proliferation of Information and Emergence of Objectivity in a Quantum Universe , 2004, arxiv : quant-ph / 0408125
  • Zurek Probabilities from entanglement, Born's rule vom envariance , 2004, arxiv : quant-ph / 0405161
  • Zurek Decoherence and the Transition from Quantum to Classical — Revisited , Los Alamos Science 2002, update of his article on decoherence in Physics Today 1991, arxiv : quant-ph / 0306072
  • Zurek Relative States and the Environment: Einselection, Envariance, Quantum Darwinism, and the Existential Interpretation , 2007, arxiv : 0707.2832
  • Quantum Darwinism on arxiv.org

Individual evidence

  1. ↑ Researchers find important evidence for quantum Darwinism Quantum dots also have a relationship life - scinexx | The knowledge magazine. Retrieved June 22, 2019 .
  2. ↑ The relationship life of the quantum dots - stability & reproduction. Retrieved June 22, 2019 .