Michael Allan Horne (January 18, 1943 – January 19, 2019) was an American

quantum In physics, a quantum (: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a property can be "quantized" is referred to as "the hypothesis of quantization". This me ...

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

, known for his work on the foundations of quantum mechanics.

Biography

Horne studied at the

University of Mississippi The University of Mississippi (Epithet, byname Ole Miss) is a Public university, public research university in University, near Oxford, Mississippi, United States, with a University of Mississippi Medical Center, medical center in Jackson, Miss ...

and earned his doctorate in physics at

Boston University Boston University (BU) is a Private university, private research university in Boston, Massachusetts, United States. BU was founded in 1839 by a group of Boston Methodism, Methodists with its original campus in Newbury (town), Vermont, Newbur ...

with

Abner Shimony Abner Eliezer Shimony (; March 10, 1928 – August 8, 2015) was an American physicist and philosopher. He specialized in quantum theory and philosophy of science. As a physicist, he concentrated on the interaction between relativity theory and q ...

. He taught at

Stonehill College Stonehill College is a private Catholic college in Easton, Massachusetts, United States. It was founded in 1948 by the Congregation of Holy Cross and is located on the original estate of Frederick Lothrop Ames Jr., with 29 buildings that compl ...

, a catholic school in Easton in the south of

Boston Boston is the capital and most populous city in the Commonwealth (U.S. state), Commonwealth of Massachusetts in the United States. The city serves as the cultural and Financial centre, financial center of New England, a region of the Northeas ...

. Together with

John Clauser John Francis Clauser (; born December 1, 1942) is an American theoretical and experimental physicist known for contributions to the foundations of quantum mechanics, in particular the Clauser–Horne–Shimony–Holt inequality. Clauser was aw ...

and Richard A. Holt he developed the

CHSH inequality In physics, the Clauser–Horne–Shimony–Holt (CHSH) inequality can be used in the proof of Bell's theorem, which states that certain consequences of entanglement in quantum mechanics cannot be reproduced by local hidden-variable theories. E ...

for experimentally testing

Bell's theorem Bell's theorem is a term encompassing a number of closely related results in physics, all of which determine that quantum mechanics is incompatible with local hidden-variable theories, given some basic assumptions about the nature of measuremen ...

(the test was conducted in 1972 by John Clauser and

Stuart Freedman Stuart Jay Freedman (January 13, 1944 – November 10, 2012) was an American physicist, known for his experiment testing Bell's inequality proposed to him by John Clauser at the University of California, Berkeley as well as for his contributions ...

). In 1975 he started to investigate

neutron interferometry In physics, a neutron interferometer is an interferometer capable of diffracting neutrons, allowing the wave-like nature of neutrons, and other related phenomena, to be explored. Interferometry Interferometry inherently depends on the wave nat ...

in collaboration with

Clifford Shull Clifford Glenwood Shull (September 23, 1915 in Pittsburgh, Pennsylvania – March 31, 2001) was an American physicist. Biography Shull attended Schenley High School in Pittsburgh, received his BS from Carnegie Institute of Technology and PhD fro ...

at MIT (at this time, neutron interference experiments were being developed by Sam Werner at the

University of Missouri The University of Missouri (Mizzou or MU) is a public university, public Land-grant university, land-grant research university in Columbia, Missouri, United States. It is Missouri's largest university and the flagship of the four-campus Univers ...

and by Helmut Rauch and

Anton Zeilinger Anton Zeilinger (; born 20 May 1945) is an Austrian quantum physicist and Nobel laureate in physics of 2022. Zeilinger is professor of physics emeritus at the University of Vienna and senior scientist at the Institute for Quantum Optics and Qu ...

at the

University of Vienna The University of Vienna (, ) is a public university, public research university in Vienna, Austria. Founded by Rudolf IV, Duke of Austria, Duke Rudolph IV in 1365, it is the oldest university in the German-speaking world and among the largest ...

). This led to an encounter with

Daniel Greenberger Daniel M. Greenberger is an American quantum physicist. He has been professor of physics at the City College of New York since 1964. He is also a fellow of the American Physical Society and—alongside Anton Zeilinger—founded the APS Topical Gr ...

, who had already theoretically proposed neutron interferometry for gravitation in the 1960s and was also interested in Shull's experiment, and later with Zeilinger (in Grenoble 1978). With

and Anton Zeilinger in 1989 he introduced quantum entangled states of three subsystems (

Greenberger–Horne–Zeilinger state In physics, in the area of quantum information theory, a Greenberger–Horne–Zeilinger (GHZ) state is an entangled quantum state that involves at least three subsystems (particle states, qubits, or qudits). Named for the three authors that ...

s) which was first experimentally realized in 1998 and represents a conceptual improvement over experiments based on Bell's inequality, as the violation with

local realism In physics, the principle of locality states that an object is influenced directly only by its immediate surroundings. A theory that includes the principle of locality is said to be a "local theory". This is an alternative to the concept of ins ...

was now a deterministic consequence predicted by quantum physics. GHZ states were the first examples of quantum entanglement with more than two particles and play a fundamental role in

quantum information theory Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both t ...

. Along with Gregg Jaeger and

, he later found a novel complementarity relation

interferometric visibility The interferometric visibility (also known as interference visibility and fringe visibility, or just visibility when in context) is a measure of the contrast of ''interference'' in any system subject to wave superposition. Examples include as opt ...

in two-particle quantum

interferometry Interferometry is a technique which uses the ''interference (wave propagation), interference'' of Superposition principle, superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important inves ...

.Gregg Jaeger, Michael A Horne, Abner Shimony, Phys. Rev. A, Volume 48, 1993, p. 1023

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Selected works

* with J. Clauser, Abner Shimony, Richard Holt: Proposed experiment to test local hidden variable theories. In: Physical Review Letters. Band 23, 1969, S. 880. * with J. Clauser: Experimental consequences of objective local theories. In: Physical Review D. Band 10, 1974, S. 526

References

External links

Website at Stonehill College

Oral History Interview, AIP, 2002

Quantum Arrangements: A volume in honor of Michael Horne
{{DEFAULTSORT:Horne, Michael 21st-century American physicists 1946 births 2019 deaths Boston University Graduate School of Arts & Sciences alumni University of Mississippi alumni 20th-century American physicists People from Gulfport, Mississippi American quantum physicists