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 caus ...

and a professor at the

KTH Royal Institute of Technology The KTH Royal Institute of Technology ( sv, Kungliga Tekniska högskolan, lit=Royal Institute of Technology), abbreviated KTH, is a public research university in Stockholm, Sweden. KTH conducts research and education in engineering and technolog ...

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

. He made major foundational contributions in

mathematical physics Mathematical physics refers to 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 t ...

and

quantum information theory Quantum information is the information of the quantum state, 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 re ...

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

Personal life

Lindblad was born in

Boden, Sweden Boden (, outdatedly ) 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, it is the second largest t ...

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 density matrix, quantum states. It is the quantum mechanical analog of relative entropy. Motivation For simplicity, it will be assumed that al ...

, 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 equation (GKSL equation, named after Vittorio Gorini, Andrzej Kossakowski, George Sudarshan and Göran Lindblad), master equation in Lindblad form, quantum Liouvillian, or Li ...

. As the

Schrödinger equation The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the ...

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 an ...

, 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 dealing with how individual quanta of light, known as photons, interact with atoms and molecules. It includes the study of the particle-like properties of photons. Photons have b ...

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 which arise from electromagnetic forces between atoms. More generally, the su ...

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

quantum communication Quantum information science is an interdisciplinary field that seeks to understand the analysis, processing, and transmission of information using quantum mechanics principles. It combines the study of Information science with quantum effects in p ...

and

computation Computation is any type of arithmetic or non-arithmetic calculation that follows a well-defined model (e.g., an algorithm). Mechanical or electronic devices (or, historically, people) that perform computations are known as ''computers''. An es ...

. 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. It does not assume or postulate any natural laws, but explains the macroscopic be ...

, 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 1940 births Living people Swedish physicists