David Deutsch

Template:Short description Template:For Template:Primary sources Template:Use dmy dates Template:Infobox scientist David Elieser Deutsch (Template:IPAc-en Template:Respell; Template:Langx; born 18 May 1953)<ref name=whoswho/> is a British physicist at the University of Oxford, often described as the "father of quantum computing".<ref>Template:Cite magazine</ref><ref>Template:Cite news</ref><ref>Template:Cite web</ref> He is a 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.<ref name="Deutsch1985">Template:Cite journal</ref> He is a proponent of the many-worlds interpretation of quantum mechanics.<ref name="scopus">Template:Scopus id</ref>

Education

Deutsch was born to a Jewish family in Haifa, Israel, on 18 May 1953, the son of Oskar and Tikva Deutsch. In London, David attended Geneva House school in Cricklewood. His parents owned and ran the Alma restaurant on Cricklewood Broadway. He later attended William Ellis School in Highgate before reading Natural Sciences at Clare College, and taking Part III of the Mathematical Tripos. He went on to Wolfson College, for his doctorate in theoretical physics,<ref name=dphd /> about quantum field theory in curved space-time,<ref name="peach">Template:Cite web</ref> supervised by Dennis Sciama<ref name=mathgene/> and Philip Candelas.<ref name=dphd>Template:Cite journal</ref>

Career and research

His work on quantum algorithms began with a 1985 paper, later expanded in 1992 along with Richard Jozsa, to produce the Deutsch–Jozsa algorithm, one of the first examples of a quantum algorithm that is exponentially faster than any possible deterministic classical algorithm.<ref name="Deutsch1985" /> In his nomination for election as a Fellow of the Royal Society (FRS) in 2008, his contributions were described as:<ref name="frs" />

Since 2012,<ref name="Merali-26052014">Template:Cite web</ref> he has been working on constructor theory, an attempt at generalising the quantum theory of computation to cover not just computation but all physical processes.<ref name="Heaven-06112012">Template:Cite web</ref><ref>Template:Cite web</ref> Together with Chiara Marletto, he published a paper in December 2014 entitled "Constructor theory of information", that conjectures that information can be expressed solely in terms of which transformations of physical systems are possible and which are impossible.<ref name="DeutschMarletto2014">Template:Cite journal</ref><ref>Template:Cite news</ref>

The Fabric of Reality

In his 1997 book The Fabric of Reality Deutsch details his views on quantum mechanics<ref>Template:Cite web</ref> and explains his "Theory of Everything". It aims not at the reduction of everything to particle physics, but rather mutual support among multiversal, computational, epistemological and evolutionary principles. His theory of everything is somewhat emergentist rather than reductive. There are four strands to his theory:

1. Hugh Everett's many-worlds interpretation of quantum physics, "the first and most important of the four strands."
2. Karl Popper's epistemology, especially its anti-inductivism and requiring a realist (non-instrumental) interpretation of scientific theories, as well as its emphasis on taking seriously those bold conjectures that resist falsification.
3. Alan Turing's theory of computation, especially as developed in Deutsch's Turing principle, in which the Universal Turing machine is replaced by Deutsch's universal quantum computer. ("The theory of computation is now the quantum theory of computation.")
4. Richard Dawkins' refinement of Darwinian evolutionary theory and the modern evolutionary synthesis, especially the ideas of replicator and meme as they integrate with Popperian problem-solving (the epistemological strand).

Invariants

In a 2009 TED talk, Deutsch expounded a criterion for scientific explanation, which is to formulate invariants: "State an explanation publicly, so that it can be dated and verified by others later that remains invariant [in the face of apparent change, new information, or unexpected conditions]".<ref name="TED">Template:Cite web Also available from YouTube Template:Webarchive</ref>

"A bad explanation is easy to vary."<ref name=TED />Template:Rp

"The search for hard-to-vary explanations is the origin of all progress"<ref name=TED />Template:Rp

"That the truth consists of hard-to-vary assertions about reality is the most important fact about the physical world."<ref name=TED />Template:Rp

Invariance as a fundamental aspect of a scientific account of reality has long been part of philosophy of science: for example, Friedel Weinert's book The Scientist as Philosopher (2004) noted the presence of the theme in many writings from around 1900 onward, such as works by Henri Poincaré (1902), Ernst Cassirer (1920), Max Born (1949 and 1953), Paul Dirac (1958), Olivier Costa de Beauregard (1966), Eugene Wigner (1967), Lawrence Sklar (1974), Michael Friedman (1983), John D. Norton (1992), Nicholas Maxwell (1993), Alan Cook (1994), Alistair Cameron Crombie (1994), Margaret Morrison (1995), Richard Feynman (1997), Robert Nozick (2001) and Tim Maudlin (2002).<ref>Template:Cite book</ref>

The Beginning of Infinity

Deutsch's second book, The Beginning of Infinity: Explanations that Transform the World, was published on 31 March 2011. In this book, he views the British Enlightenment of the 17th and 18th centuries as near the beginning of a potentially unending sequence of purposeful knowledge creation. He examines the nature of knowledge, memes, and how and why creativity evolved in humans.<ref>Deutsch David, The Beginning of Infinity, pages 369-398</ref>

Awards and honours

The Fabric of Reality was shortlisted for the Rhone-Poulenc science book award in 1998. Deutsch was awarded the Dirac Prize of the Institute of Physics in 1998,<ref name=":0">Template:Cite web</ref> and the Edge of Computation Science Prize in 2005.<ref>Template:Cite web</ref> In 2017, he received the Dirac Medal of the International Centre for Theoretical Physics (ICTP).<ref>Template:Cite web</ref> Deutsch is linked to Paul Dirac through his doctoral advisor Dennis Sciama, whose doctoral advisor was Dirac. Deutsch was elected a fellow of the Royal Society (FRS) in 2008.<ref name="frs">Template:Cite web One or more of the preceding sentences incorporates text from the royalsociety.org website where: "All text published under the heading 'Biography' on Fellow profile pages is available under Creative Commons Attribution 4.0 International License." –Template:Cite web</ref> In 2018, he received the Micius Quantum Prize. In 2021, he was awarded the Isaac Newton Medal and Prize.<ref>Template:Cite web</ref> On September 22, 2022, he was awarded the Breakthrough Prize in Fundamental Physics, shared with Charles H. Bennet, Gilles Brassard and Peter Shor.<ref>Template:Cite web</ref>

Personal life

Deutsch is a founding member of the parenting and educational method Taking Children Seriously.<ref>Template:Cite web</ref>

Views on Antisemitism and Zionism

Deutsch describes antisemitism as a recurring pattern of irrational thinking, present in many cultures, whose function is to justify harming Jews simply for being Jews.<ref name=":02">Template:Cite web</ref><ref name=":1">Template:Cite web</ref> He argues that "the pattern" persists because, when old justifications for hating Jews lose relevance, new ones are invented to take their place.<ref>Template:Cite book</ref><ref name=":1" /> Deutsch compares this phenomenon to the way gold retains its high value, not because of any inherent quality, but because people know that other people value it.<ref name=":1" /> He regards Zionism as the contemporary Jewish response to this pattern and identifies himself as an atheist Zionist.<ref name=":02" /><ref>Template:Cite web</ref>

Views on Brexit

Deutsch supported Brexit, with his advocacy quoted by then-government adviser, Dominic Cummings, and reported by The New Yorker in January 2020.<ref>Template:Cite magazine</ref>

Michael Gove mentioned Deutsch's viewpoint during a BBC Brexit debate. Regarding the debate, Deutsch later commented:

In Britain there is a clear path if you have a grievance, you can join a pressure-group, the pressure-group will pressure the government, or you can see your MP, and the MP will see the grievance building up, and so-on. Whereas, Europe is structured in such a way that it's very difficult to know whom to address your grievance to, or what they could do about it.<ref name=cummings />

Deutsch was not involved in any campaign advocacy for Brexit. His public remarks on the subject were quoted by Cummings and Gove on their own initiative, as Deutsch later made clear.<ref name="cummings">Template:Cite web</ref>Template:Rp<ref name="gove">Template:Cite web</ref>Template:Rp

See also

• Deutsch gate
• Wigner's friend
• Quantum cellular automaton
• Quantum mechanics of time travel