Many-worlds interpretation. The quantum-mechanical "Schrödinger's cat" paradox according to the many-worlds interpretation. In this interpretation, every event is a branch point; the cat is both alive and dead, even before the box is opened, but the "alive" and "dead" cats are in different branches of the universe, both of which are equally real, but which do not interact with each other.[1] The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse.
Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In lay terms, the hypothesis states there is a very large—perhaps infinite[2]—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes. Outline[edit] Interpreting wavefunction collapse[edit] Probability[edit] where. Hong–Ou–Mandel effect.
Quantum-mechanical description[edit] Physical description[edit] When a photon enters a beam splitter, there are two possibilities: it will either be reflected or transmitted. The relative probabilities of transmission and reflection are determined by the reflectivity of the beam splitter. Here, we assume a 50:50 beam splitter, in which a photon has equal probability of being reflected and transmitted. Figure 1. Since the state of the beam splitter does not "record" which of the four possibilities actually happens, Feynman's rule dictates that we have to add all four possibilities at the amplitude level.
Mathematical description[edit] Consider two optical modes a and b that carry annihilation and creation operators , and . Where is a single-photon state. Unitarity of the transformation now means unitarity of the matrix. When two photons enter the beam splitter, one on each side, the state of the two modes becomes Since the commutator of the two creation operators and . Figure 2. By: If. 404 Not Found. David Deutsch Video Lectures. Quantenphysiker David Deutsch: "Ich existiere unendlich oft" David Deutsch. David Elieser Deutsch, FRS (born 1953 in Haifa, Israel) is a British physicist at the University of Oxford. He is a non-stipendiary Visiting Professor in the Department of Atomic and Laser Physics at the Centre for Quantum Computation (CQC) in the Clarendon Laboratory of the University of Oxford.
He pioneered the field of quantum computation by formulating a description for a quantum Turing machine, as well as specifying an algorithm designed to run on a quantum computer.[2] He is a proponent of the many-worlds interpretation of quantum mechanics. Career[edit] In the Royal Society of London's announcement that Deutsch had become a Fellow of the Royal Society (FRS) in 2008, the Society described Deutsch's contributions thus:[3] He is currently working on constructor theory, an attempt at generalizing the quantum theory of computation to cover not just computation but all physical processes.[4] Popular science books[edit] The Fabric of Reality[edit] There are "four strands" to his theory: David Deutsch (Wissenschaftler) David Deutsch (* 1953 in Haifa ) ist ein israelisch-britischer Physiker auf dem Gebiet der Quanteninformationstheorie . Leben [ Bearbeiten ] Deutsch studierte Mathematik und Physik in Cambridge , Oxford und Austin und ist seit 2009 Inhaber eines Lehrstuhls an der Universität Oxford .
Er erhielt den Dirac-Preis 1998 für seine Arbeiten zum Quantencomputer , u. a. darüber, wie diese Maschinen durch Quantengatter realisiert werden könnten. Deutsch ist einer der bekanntesten Vertreter der sogenannten Viele-Welten-Interpretation der Quantenmechanik. Aus dem Doppelspaltexperiment der Quantenmechanik zieht Deutsch in seinem Buch The Fabric of Reality auf dieser Grundlage den Schluss, dass parallele Universen sehr konkret das Universum beeinflussen, z. B. die Intensitätsverteilung der Photonen im Doppelspaltexperiment, wo einzelne Teilchen ohne sichtbare Wechselwirkungspartner ein Interferenzmuster erzeugen.
Nach ihm ist der Deutsch-Jozsa-Algorithmus benannt. Literatur [ Bearbeiten ]