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 earned a certificate of advanced study in mathematics and a master of philosophy degree from Cambridge University in 1983 and 1984, while on a Marshall Scholarship. [2] Lloyd was awarded a doctorate by Rockefeller University in 1988 (advisor Heinz Pagels) after submitting a thesis on Black Holes, Demons, and the Loss of Coherence: How Complex Systems Get Information, and What They Do With It.
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. Starting in 1988, Lloyd was an external faculty member at the Santa Fe Institute for more than 30 years.
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. [3] 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. [4] He has made influential contributions to a broad range of topics, mostly in the wider field of quantum information science. Among his most cited works are the first proposal for a digital quantum simulator [5] , a general framework for quantum metrology [6] , the first treatment of quantum computation with continuous variables, [7] dynamical decoupling as a method of quantum error avoidance, [8] quantum algorithms for equation solving [9] and machine learning [10] [11] or research on the possible relevance of quantum effects in biological phenomena, especially photosynthesis, [12] [13] [14] an effect he has also collaborated to exploit technologically. [15]
According to Clarivate he had in July 2023 in total 199 peer-reviewed publications which were cited more than 22,600 times leading to an h index of 61. [16]
Epstein affair
During July 2019, reports surfaced that MIT and other institutions had accepted funding from convicted sex offender Jeffrey Epstein. [17] In the ensuing scandal, [18] the director of the MIT Media Lab, Joi Ito, resigned from MIT as a result of his association with Epstein. [19] Lloyd's connections to Epstein also drew criticism: Lloyd had acknowledged receiving funding from Epstein in 19 of his papers. [20] On August 22, 2019, Lloyd published a letter [21] apologizing for accepting grants (totaling $225,000) from Epstein. Despite this, the controversy continued. [22] [23] [24] In January 2020, at the request of the MIT Corporation, the law firm Goodwin Procter issued a report [18] 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. [25] Lloyd has vigorously denied that he misled MIT about the source of the funds he received from Epstein. [26] This denial was validated by a subsequent MIT investigation that concluded that Lloyd did not attempt to circumvent the MIT vetting process, nor try to conceal the name of the donor, and Lloyd was allowed to continue his tenured faculty position at MIT. [27] However, most but not all members of MIT's fact-finding committee concluded that Lloyd had violated MIT's conflict of interest policy by not revealing crucial publicly known information about Epstein's background to MIT, as a result of which Lloyd will be subject to a series of administrative actions for 5 years. [27]
Quantum entanglement is the phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in a way such that the quantum state of each particle of the group cannot be described independently of the state of the others, including when the particles are separated by a large distance. The topic of quantum entanglement is at the heart of the disparity between classical and quantum physics: entanglement is a primary feature of quantum mechanics not present in classical mechanics.
In quantum computing, a quantum algorithm is an algorithm which runs on a realistic model of quantum computation, the most commonly used model being the quantum circuit model of computation. A classical algorithm is a finite sequence of instructions, or a step-by-step procedure for solving a problem, where each step or instruction can be performed on a classical computer. Similarly, a quantum algorithm is a step-by-step procedure, where each of the steps can be performed on a quantum computer. Although all classical algorithms can also be performed on a quantum computer, the term quantum algorithm is usually used for those algorithms which seem inherently quantum, or use some essential feature of quantum computation such as quantum superposition or quantum entanglement.
Quantum Darwinism is a theory meant to explain the emergence of the classical world from the quantum world as due to a process of Darwinian natural selection induced by the environment interacting with the quantum system; where the many possible quantum states are selected against in favor of a stable pointer state. It was proposed in 2003 by Wojciech Zurek and a group of collaborators including Ollivier, Poulin, Paz and Blume-Kohout. The development of the theory is due to the integration of a number of Zurek's research topics pursued over the course of 25 years, including pointer states, einselection and decoherence.
Artur Konrad Ekert is a British-Polish professor of quantum physics at the Mathematical Institute, University of Oxford, professorial fellow in quantum physics and cryptography at Merton College, Oxford, Lee Kong Chian Centennial Professor at the National University of Singapore and the founding director of the Centre for Quantum Technologies (CQT). His research interests extend over most aspects of information processing in quantum-mechanical systems, with a focus on quantum communication and quantum computation. He is best known as one of the pioneers of quantum cryptography.
Within quantum technology, a quantum sensor utilizes properties of quantum mechanics, such as quantum entanglement, quantum interference, and quantum state squeezing, which have optimized precision and beat current limits in sensor technology. The field of quantum sensing deals with the design and engineering of quantum sources and quantum measurements that are able to beat the performance of any classical strategy in a number of technological applications. This can be done with photonic systems or solid state systems.
Andrew G. White FAA is an Australian scientist and is currently Professor of Physics and a Vice-Chancellor's Senior Research Fellow at the University of Queensland. He is also Director of the University of Queensland Quantum technology Laboratory; Deputy-Director of the ARC Centre for Engineered Quantum systems, and a Program Manager in the ARC Centre for Quantum Computer and Communication Technology..
In quantum information theory, quantum discord is a measure of nonclassical correlations between two subsystems of a quantum system. It includes correlations that are due to quantum physical effects but do not necessarily involve quantum entanglement.
Dynamical decoupling (DD) is an open-loop quantum control technique employed in quantum computing to suppress decoherence by taking advantage of rapid, time-dependent control modulation. In its simplest form, DD is implemented by periodic sequences of instantaneous control pulses, whose net effect is to approximately average the unwanted system-environment coupling to zero. Different schemes exist for designing DD protocols that use realistic bounded-strength control pulses, as well as for achieving high-order error suppression, and for making DD compatible with quantum gates. In spin systems in particular, commonly used protocols for dynamical decoupling include the Carr-Purcell and the Carr-Purcell-Meiboom-Gill schemes. They are based on the Hahn spin echo technique of applying periodic pulses to enable refocusing and hence extend the coherence times of qubits.
Quantum machine learning is the integration of quantum algorithms within machine learning programs. The most common use of the term refers to machine learning algorithms for the analysis of classical data executed on a quantum computer, i.e. quantum-enhanced machine learning. While machine learning algorithms are used to compute immense quantities of data, quantum machine learning utilizes qubits and quantum operations or specialized quantum systems to improve computational speed and data storage done by algorithms in a program. This includes hybrid methods that involve both classical and quantum processing, where computationally difficult subroutines are outsourced to a quantum device. These routines can be more complex in nature and executed faster on a quantum computer. Furthermore, quantum algorithms can be used to analyze quantum states instead of classical data. Beyond quantum computing, the term "quantum machine learning" is also associated with classical machine learning methods applied to data generated from quantum experiments, such as learning the phase transitions of a quantum system or creating new quantum experiments. Quantum machine learning also extends to a branch of research that explores methodological and structural similarities between certain physical systems and learning systems, in particular neural networks. For example, some mathematical and numerical techniques from quantum physics are applicable to classical deep learning and vice versa. Furthermore, researchers investigate more abstract notions of learning theory with respect to quantum information, sometimes referred to as "quantum learning theory".
Quantum feedback or quantum feedback control is a class of methods to prepare and manipulate a quantum system in which that system's quantum state or trajectory is used to evolve the system towards some desired outcome. Just as in the classical case, feedback occurs when outputs from the system are used as inputs that control the dynamics. The feedback signal is typically filtered or processed in a classical way, which is often described as measurement based feedback. However, quantum feedback also allows the possibility of maintaining the quantum coherence of the output as the signal is processed, which has no classical analogue.
Edward Farhi is physicist working on quantum computation as a Principal Scientist at Google. In 2018 he retired from his position as the Cecil and Ida Green Professor of Physics at the Massachusetts Institute of Technology. He was the Director of the Center for Theoretical Physics at MIT from 2004 until 2016. He made contributions to particle physics, general relativity and astroparticle physics before turning to his current interest, quantum computation.
Sandu Popescu is a Romanian-British physicist working in the foundations of quantum mechanics and quantum information.
In quantum computing, quantum supremacy, quantum primacy or quantum advantage is the goal of demonstrating that a programmable quantum computer can solve a problem that no classical computer can solve in any feasible amount of time, irrespective of the usefulness of the problem. The term was coined by John Preskill in 2012, but the concept dates back to Yuri Manin's 1980 and Richard Feynman's 1981 proposals of quantum computing.
Aram Wettroth Harrow is a professor of physics in the Massachusetts Institute of Technology's Center for Theoretical Physics.
Simone Severini is an Italian-born British computer scientist. He is currently Professor of Physics of Information at University College London, and Director of Quantum Computing at Amazon Web Services.
Continuous-variable (CV) quantum information is the area of quantum information science that makes use of physical observables, like the strength of an electromagnetic field, whose numerical values belong to continuous intervals. One primary application is quantum computing. In a sense, continuous-variable quantum computation is "analog", while quantum computation using qubits is "digital." In more technical terms, the former makes use of Hilbert spaces that are infinite-dimensional, while the Hilbert spaces for systems comprising collections of qubits are finite-dimensional. One motivation for studying continuous-variable quantum computation is to understand what resources are necessary to make quantum computers more powerful than classical ones.
In quantum computing, a qubit is a unit of information analogous to a bit in classical computing, but it is affected by quantum mechanical properties such as superposition and entanglement which allow qubits to be in some ways more powerful than classical bits for some tasks. Qubits are used in quantum circuits and quantum algorithms composed of quantum logic gates to solve computational problems, where they are used for input/output and intermediate computations.
In quantum mechanics, a quantum speed limit (QSL) is a limitation on the minimum time for a quantum system to evolve between two distinguishable states. QSL are closely related to time-energy uncertainty relations. In 1945, Leonid Mandelstam and Igor Tamm derived a time-energy uncertainty relation that bounds the speed of evolution in terms of the energy dispersion. Over half a century later, Norman Margolus and Lev Levitin showed that the speed of evolution cannot exceed the mean energy, a result known as the Margolus–Levitin theorem. Realistic physical systems in contact with an environment are known as open quantum systems and their evolution is also subject to QSL. Quite remarkably it was shown that environmental effects, such as non-Markovian dynamics can speed up quantum processes, which was verified in a cavity QED experiment.
Ivette Fuentes is a Professor of Quantum Physics at the University of Southampton and Professor of Theoretical Quantum Optics at the University of Vienna. Her work considers fundamental quantum mechanics, quantum optics and astrophysics. She is interested in how quantum information theory can make use of relativistic effects.
