Norman H. Margolus (born 1955) is a Canadian-American

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 ...

and

computer scientist A computer scientist is a scientist who specializes in the academic study of computer science. Computer scientists typically work on the theoretical side of computation. Although computer scientists can also focus their work and research on ...

, known for his work on

cellular automata A cellular automaton (pl. cellular automata, abbrev. CA) is a discrete model of computation studied in automata theory. Cellular automata are also called cellular spaces, tessellation automata, homogeneous structures, cellular structures, tessel ...

and

reversible computing Reversible computing is any model of computation where every step of the process is time-reversible. This means that, given the output of a computation, it's possible to perfectly reconstruct the input. In systems that progress deterministica ...

.. He is a research affiliate with the

Computer Science and Artificial Intelligence Laboratory Computer Science and Artificial Intelligence Laboratory (CSAIL) is a research institute at the Massachusetts Institute of Technology (MIT) formed by the 2003 merger of the Laboratory for Computer Science (LCS) and the Artificial Intelligence Lab ...

at the

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...

Education and career

Margolus received his Ph.D. in physics in 1987 from the

(MIT) under the supervision of Edward Fredkin. He founded and was chief scientist for

Permabit Permabit Technology Corporation was a private supplier of data reduction solutions to the computer data storage industry. On 31 July 2017 it was announced that Red Hat had acquired the assets and technology of Permabit Technology Corporation. Pe ...

, an information storage device company.

Research contributions

Margolus was one of the organizers of a seminal research meeting on the connections between physics and computation theory, held on

Mosquito Island Moskito Island (sometimes spelled Mosquito Island) is an island off the coast of Virgin Gorda and has long been a favourite for scuba divers and sailors. For many years the island was the location of a sail-in dive resort named Drake's Anchor ...

in 1982. He is known for inventing the

block cellular automaton A block cellular automaton or partitioning cellular automaton is a special kind of cellular automaton in which the lattice of cells is divided into non-overlapping blocks (with different partitions at different time steps) and the transition rule ...

and the Margolus neighborhood for block cellular automata, which he used to develop cellular automaton simulations of

billiard-ball computer A billiard-ball computer, a type of conservative logic circuit, is an idealized model of a reversible computing, reversible mechanical computer based on Newtonian dynamics, proposed in 1982 by Edward Fredkin and Tommaso Toffoli. Instead of using ...

s.. Reprinted in . In the same work, Margolus also showed that the billiard ball model could be simulated by a

second-order cellular automaton A second-order cellular automaton is a type of reversible cellular automaton (CA) invented by Edward Fredkin. Reprinted in . where the state of a cell at time depends not only on its neighborhood at time , but also on its state at time .. Gene ...

, a different type of cellular automaton invented by his thesis advisor,

Edward Fredkin Edward Fredkin (October 2, 1934 – June 13, 2023) was an American computer scientist, physicist and businessman who was an early pioneer of digital physics. Fredkin's primary contributions included work on reversible computing and cellular au ...

. These two simulations were among the first cellular automata that were both reversible (able to be run backwards as well as forwards for any number of time steps, without ambiguity) and

universal Universal is the adjective for universe. Universal may also refer to: Companies * NBCUniversal, a media and entertainment company that is a subsidiary of Comcast ** Universal Animation Studios, an American Animation studio, and a subsidiary of N ...

(able to simulate the operations of any computer program); this combination of properties is important in low-energy computing, as it has been shown that the energy dissipation of computing devices may be made arbitrarily small if and only if they are reversible. In connection with this issue, Margolus and his co-author Lev B. Levitin proved the

Margolus–Levitin theorem In quantum mechanics, a quantum speed limit (QSL) is a limitation on the minimum time for a quantum system to evolve between two distinguishable (orthogonal) states. QSL theorems are closely related to time-energy uncertainty relations. In 1945, Le ...

showing that the speed of any computer is limited by the fundamental laws of physics to be at most proportional to its energy use; this implies that ultra-low-energy computers must run more slowly than conventional computers. With

Tommaso Toffoli Tommaso Toffoli () is an Italian-American professor of electrical and computer engineering at Boston University where he joined the faculty in 1995. He has worked on cellular automata and the theory of artificial life (with Edward Fredkin and othe ...

, Margolus developed the CAM-6 cellular automaton simulation hardware, which he extensively described in his book with Toffoli, ''Cellular Automata Machines'' (MIT Press, 1987), and with Tom Knight he developed the "Flattop"

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

implementation of billiard-ball computation. He has also done pioneering research on the reversible

quantum gate In quantum computing and specifically the quantum circuit model of computation, a quantum logic gate (or simply quantum gate) is a basic quantum circuit operating on a small number of qubits. Quantum logic gates are the building blocks of quantu ...

logic needed to support

quantum computer A quantum computer is a computer that exploits quantum mechanical phenomena. On small scales, physical matter exhibits properties of both particles and waves, and quantum computing takes advantage of this behavior using specialized hardware. ...

s..

References

External links

Margolus' web site
at MIT {{DEFAULTSORT:Margolus, Norman 1955 births Living people American computer scientists 21st-century American physicists Cellular automatists Massachusetts Institute of Technology School of Science alumni University of Alberta alumni

Education and career

Research contributions

See also

References

External links