Göran Lindblad (9 July 1940 – 30 November 2022) was a Swedish theoretical

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 a professor at the

KTH Royal Institute of Technology KTH Royal Institute of Technology (), abbreviated KTH, is a Public university, public research university in Stockholm, Sweden. KTH conducts research and education in Institute of technology, engineering and technology and is Sweden's largest te ...

Stockholm Stockholm (; ) is the Capital city, capital and List of urban areas in Sweden by population, most populous city of Sweden, as well as the List of urban areas in the Nordic countries, largest urban area in the Nordic countries. Approximately ...

. He made major foundational contributions in

mathematical physics Mathematical physics is the development of mathematics, mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and the de ...

and

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 ...

, having to do with open quantum systems, entropy inequalities, and quantum measurements.

Personal life

Lindblad was born in

Boden, Sweden Boden (, outdatedly , Lule Sámi: ''Suttes'') is a locality and the seat of Boden Municipality in Norrbotten County, Sweden, with 16,847 inhabitants in 2018. It is part of the larger area around coastal city Luleå some southeast. After Kiruna, ...

on July 9, 1940, and grew up in Örebro, Sweden. Besides physics, he took an interest in history. He died on November 30, 2022, near his home in Johanneshov, Sweden.

Career

Lindblad spent his entire career, starting from his undergraduate days, at the

. He defended his PhD thesis, entitled "The concepts of information and entropy applied to the measurement process in quantum theory and statistical mechanics," on May 29, 1974. His PhD thesis summarized the contents of some important contributions to

, including his proof of the data-processing inequality for

quantum relative entropy In quantum information theory, quantum relative entropy is a measure of distinguishability between two quantum states. It is the quantum mechanical analog of relative entropy. Motivation For simplicity, it will be assumed that all objects in ...

, communicated in a series of three research publications. Shortly after his PhD thesis work, he derived his most well known scientific contribution, what is known as the

Lindblad equation In quantum mechanics, the Gorini–Kossakowski–Sudarshan–Lindblad (GKSL) equation (named after Vittorio Gorini, Andrzej Kossakowski, E. C. George Sudarshan, George Sudarshan and Göran Lindblad (physicist), Göran Lindblad), master equation in ...

. As the

Schrödinger equation The Schrödinger equation is a partial differential equation that governs the wave function of a non-relativistic quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. It is named after E ...

describes the evolution of a closed quantum system, the

is a generalization, describing the evolution of an

open quantum system In physics, an open quantum system is a quantum-mechanical system that interacts with an external quantum system, which is known as the ''environment'' or a ''bath''. In general, these interactions significantly change the dynamics of the system a ...

, in which a system of interest is interacting with an uncontrollable environment. The Lindblad equation is a significant theoretical contribution and is widely used in many fields of physics, including

quantum optics Quantum optics is a branch of atomic, molecular, and optical physics and quantum chemistry that studies the behavior of photons (individual quanta of light). It includes the study of the particle-like properties of photons and their interaction ...

and

condensed matter Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid phases, that arise from electromagnetic forces between atoms and electrons. More gen ...

. It is also now the most common method for describing noise that affects various quantum technologies, in the domains of

quantum communication In quantum information theory, a quantum channel is a communication channel that can transmit quantum information, as well as classical information. An example of quantum information is the general dynamics of a qubit. An example of classical in ...

and

computation A computation is any type of arithmetic or non-arithmetic calculation that is well-defined. Common examples of computation are mathematical equation solving and the execution of computer algorithms. Mechanical or electronic devices (or, hist ...

. He published a monograph on two related conceptual problems in the foundations of

statistical mechanics In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. Sometimes called statistical physics or statistical thermodynamics, its applicati ...

, concerning the derivation of the irreversibility of the observed macroscopic behavior from the reversible microscopic laws of motion and the definition of an entropy function on non-equilibrium quantum states. He retired on July 1, 2005, and was a professor emeritus since that time.

References

{{DEFAULTSORT:Lindblad, Goran Swedish physicists Quantum physicists 1940 births 2022 deaths People from Boden, Sweden