Seth Lloyd

Seth Lloyd (born August 2, 1960) is an American quantum information scientist and professor in the Massachusetts Institute of Technology Department of Mechanical Engineering.

Seth Lloyd
Seth Lloyd in 2013
Born	(1960-08-02) August 2, 1960 (age 64)
Nationality	American
Education	Phillips Academy (1978) Harvard College (A.B., 1982) Cambridge University (M.Phil, 1984) Rockefeller University (Ph.D. physics, 1988)
Known for	Coherent information Continuous-variable quantum information Dynamical decoupling Effective complexity HHL algorithm Quantum capacity Quantum illumination Quantum mechanics of time travel
Scientific career
Fields	Physicist
Institutions	Massachusetts Institute of Technology California Institute of Technology Los Alamos National Laboratory Santa Fe Institute
Doctoral advisor	Heinz Pagels

He has done seminal work in quantum computation, quantum communication and quantum biology, including proposing the first feasible design for a quantum computer, demonstrating the viability of quantum analog computation, proving quantum analogs of Shannon's theorem, and designing novel methods for quantum error correction and noise reduction.^[1]

Biography

Lloyd was born on August 2, 1960. He graduated from Phillips Academy in 1978 and received a Bachelor of Arts degree from Harvard College in 1982. He completed Part III and an MPhil from Cambridge University in 1983 and 1984, while on a Marshall Scholarship.^[2] Lloyd completed a PhD in physics at Rockefeller University in 1988, advised by Heinz Pagels.

From 1988 to 1991, Lloyd was a postdoctoral fellow in the High Energy Physics Department at the California Institute of Technology, where he worked with Murray Gell-Mann on applications of information to quantum-mechanical systems. From 1991 to 1994, he was a postdoctoral fellow at Los Alamos National Laboratory, where he worked at the Center for Nonlinear Systems on quantum computation. In 1994, he joined the faculty of the Department of Mechanical Engineering at MIT. Lloyd was an external faculty member at the Santa Fe Institute.

In 2007 he was named a Fellow of the American Physical Society.^[3] In 2012 he was given the International Quantum Communication Award.^[4]

Work

In his 2006 book, Programming the Universe, Lloyd contends that the universe itself is one big quantum computer producing what we see around us, and ourselves, as it runs a cosmic program. According to Lloyd, once we understand the laws of physics completely, we will be able to use small-scale quantum computing to understand the universe completely as well.

Lloyd states that we could have the whole universe simulated in a computer in 600 years provided that computational power increases according to Moore's Law.^[5] However, Lloyd shows that there are limits to rapid exponential growth in a finite universe, and that it is very unlikely that Moore's Law will be maintained indefinitely.

Lloyd directs the Center for Extreme Quantum Information Theory (xQIT) at MIT.^[6] He has made contributions to a range of topics, mainly in quantum information science. Among his most cited works are the first proposal for a digital quantum simulator,^[7] a general framework for quantum metrology,^[8] the first treatment of continuous-variable quantum information,^[9] dynamical decoupling as a method of quantum error avoidance,^[10] and research on the possible relevance of quantum effects in biological phenomena, especially photosynthesis,^[11][12] an effect he has also collaborated to exploit technologically.^[13]

With Aram Harrow and Avinatan Hassidim he introduced the HHL algorithm^[14] for solving systems of linear equations, and later several quantum machine learning algorithms based on it.^[15][16] These algorithms were widely thought to give an exponential speedup relative to the best classical algorithms, until the discovery by Ewin Tang of classical algorithms achieving the same exponential speedup.^[17]

Epstein affair

During July 2019, reports surfaced that MIT and other institutions had accepted funding from convicted sex offender Jeffrey Epstein.^[18] In the ensuing scandal, Joi Ito, the director of the MIT Media Lab, resigned from MIT as a result of his association with Epstein.^[19][20] Lloyd had been introduced to Epstein at the Edge Billionaires' Dinner in 2004 by his literary agent John Brockman, who had close connections to Epstein.^[21] Brockman had also previously introduced Lloyd to Ito in February 2004.^[22]

Lloyd's close connections to Epstein drew substantial criticism, having acknowledged funding from Epstein in 19 papers,^[23] visiting Epstein's private island,^[24] and visiting Epstein in prison after his first conviction.^[25] Lloyd also received backlash for discussing his relationship with Epstein during an undergraduate quantum computing course he taught.^[26][24]

On August 22, 2019, Lloyd published a letter apologizing for accepting grants totaling $225,000 from Epstein.^[25] The controversy at MIT continued despite this, including student protests demanding Lloyd's resignation.^[27][26][28] In January 2020, at the request of the MIT Corporation, the law firm Goodwin Procter issued a report^[19] on all of MIT's interactions with Epstein. As a result of the report, on January 10, 2020, Lloyd was placed on paid administrative leave.^[29]

Lloyd has denied that he misled MIT about the source of the funds he received from Epstein.^[30] A subsequent MIT investigation concluded that Lloyd did not attempt to circumvent the MIT vetting process, and Lloyd was allowed to keep his tenured faculty position.^[31] However, most members of MIT's fact-finding committee concluded that Lloyd had violated MIT policy by not disclosing certain publicly known information about Epstein's background. Lloyd was then subject to a series of disciplinary actions over the next 5 years, including limits on his ability to solicit donors and to advise students.^[31][32]

Personal life

Lloyd's mother was Susan Lloyd, a history teacher at Phillips Andover.^[33][34] His maternal grandparents were Rustin McIntosh, a pediatrician, and Millicent Carey McIntosh, an educational administrator.^[33] His father, Robert Lloyd, was an art teacher at Phillips Andover ^[33][35] His paternal grandparents were teachers of history and dance at Phillips Exeter.^[35]

Selected publications

• Lloyd, Seth (1988). Black Holes, Demons and the Loss of Coherence: How complex systems get information, and what they do with it (PDF) (Ph.D. thesis). The Rockefeller University. Archived from the original (PDF) on 2012-06-07.
• Lloyd, S. (2000-08-31). "Ultimate physical limits to computation". Nature. 406 (6799): 1047–1054. arXiv:quant-ph/9908043v3. Bibcode:2000Natur.406.1047L. doi:10.1038/35023282. PMID 10984064. S2CID 75923.
• Lloyd, Seth (2001-10-24). "Computational capacity of the universe". Physical Review Letters. 88 (23): 237901. arXiv:quant-ph/0110141. doi:10.1103/PhysRevLett.88.237901. PMID 12059399. S2CID 6341263.
• Lloyd, S., Programming the Universe: A Quantum Computer Scientist Takes On the Cosmos, Knopf, March 14, 2006, 240 p., ISBN 1-4000-4092-2
• Lloyd, Seth (2008). "Quantum Mechanics and Emergence". In Abbott, Derek; Davies, Paul C. W.; Pati, Arun K. (eds.). Quantum Aspects of Life. Imperial College Press. ISBN 978-1848162532.
• Movie: In 2022 Lloyd starred in the short film Steeplechase directed by Andrey Kezzyn,^[36] which thematizes closed timelike curves, a topic Lloyd has also addressed in his scientific work.^[37]