Helmut Ritsch (; born 12 March 1962 in

Innsbruck Innsbruck (; bar, Innschbruck, label=Bavarian language, Austro-Bavarian ) is the capital of Tyrol (state), Tyrol and the List of cities and towns in Austria, fifth-largest city in Austria. On the Inn (river), River Inn, at its junction with the ...

) is an

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

quantum physicist Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, qua ...

and a professor of

theoretical physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experim ...

at the

University of Innsbruck The University of Innsbruck (german: Leopold-Franzens-Universität Innsbruck; la, Universitas Leopoldino Franciscea) is a public research university in Innsbruck, the capital of the Austrian federal state of Tyrol, founded on October 15, 1669. ...

. Helmut Ritsch's research concerns the fundamental aspects and applications of

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

cavity quantum electrodynamics Cavity quantum electrodynamics (cavity QED) is the study of the interaction between light confined in a reflective cavity and atoms or other particles, under conditions where the quantum nature of photons is significant. It could in principle be us ...

. Together with his theory group, he focuses on

cavity Cavity may refer to: Biology and healthcare *Body cavity, a fluid-filled space in many animals where organs typically develop **Gastrovascular cavity, the primary organ of digestion and circulation in cnidarians and flatworms *Dental cavity or too ...

cooling, self-organization,

quantum thermodynamics Quantum thermodynamics is the study of the relations between two independent physical theories: thermodynamics and quantum mechanics. The two independent theories address the physical phenomena of light and matter. In 1905, Albert Einstein argued ...

, light forces, superradiant lasing and

quantum metrology Quantum metrology is the study of making high-resolution and highly sensitive measurements of physical parameters using quantum theory to describe the physical systems, particularly exploiting quantum entanglement and quantum squeezing. This fie ...

. His significant contributions in those fields have been honoured with prestigious awards and prizes, as the

Ludwig Boltzmann Prize The Ludwig Boltzmann Prize is awarded by the Austrian Physical Society and honors outstanding achievements in theoretical physics. It is named after the famous Austrian physicist Ludwig Boltzmann. The prize was established at the annual meeting ...

(1993) of the

Austrian Physical Society The Austrian Physical Society (german: Österreichische Physikalische Gesellschaft) is the national physical society of Austria. History Until 1938, Austrian physicists were part of the German Physical Society. On 13 December 1950, it was decide ...

and the

Erwin Schrödinger Prize The Erwin Schrödinger Prize (German: Erwin Schrödinger-Preis) is an annual award presented by the Austrian Academy of Sciences for lifetime achievement by Austrians in the fields of mathematics and natural sciences. The prize was established i ...

(2019) of the Austrian Academy of Sciences.

Life and career

Ritsch grew up in

Stubaital The Stubaital is an alpine valley in Tyrol, Austria. It is the central valley of the Stubai Alps. The river Ruetz flows through the valley. This 35-km long valley runs in northeastern direction from the main chain of the Alps to Schönberg im S ...

in the neighbourhood of

. He graduated in 1980 from Akademischen Gymnasium in Innsbruck and studied physics at the

, where he finished his diploma study in 1985 with a thesis about synchrotron radiation. He began his doctoral studies under

Peter Zoller Peter may refer to: People * List of people named Peter, a list of people and fictional characters with the given name * Peter (given name) ** Saint Peter (died 60s), apostle of Jesus, leader of the early Christian Church * Peter (surname), a su ...

, which he finished in 1989 with the dissertation "Atomic Dynamics in Classical Stochastic and Quantum Light Fields". Afterwards he worked as a postdoc in Innsbruck, Konstanz, Milan, Boulder and Munich. In 1993 he was habilitated at the

(venia docendi in theoretical physics). In 1996/97 Ritsch did research at the

University of Milan The University of Milan ( it, Università degli Studi di Milano; la, Universitas Studiorum Mediolanensis), known colloquially as UniMi or Statale, is a public research university in Milan, Italy. It is one of the largest universities in Europe ...

as part of a Marie Skłodowska-Curie project. Beginning in 1998, he was associate professor, and since 2011 Helmut Ritsch is professor at the Institute for Theoretical Physics at the

. He was the head of the institute from 2009 until 2013 and from 2017 until 2021. Helmut Ritsch is married to the physicist Monika Ritsch-Marte, they have two daughters.

Research

Cavity QED

Helmut Ritsch has made significant contributions to the field of cavity quantum electrodynamics (QED), in particular to many-body cavity QED. Along his colleagues, he has developed the notion of self-organization of atoms interacting strongly with quantized radiation fields of high-Q cavities, as a manifestation of the Dicke superradiant

phase transition In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of ...

. This phenomenon has been observed in many experiments, ranging from Bose-Einstein condensates to non-interacting and strongly interacting Fermi gases. The atomic self-organization in cavities is currently an active field of research, with the prospect to address some of the most challenging, open questions in nonequilibrium many-body physics in a controlled way.

Monte Carlo wave function (MCWF) method

Monte Carlo wave function method, also known as quantum jump method, is a computational tool used in dissipative systems to approximate the density matrix of a quantum system. The method was developed in 1992 independently by Dum, Zoller and Ritsch and Dalibard, Castin and Mølmer.

QuantumOptics.jl

QuantumOptics.jl is a numerical framework written in the

Julia Julia is usually a feminine given name. It is a Latinate feminine form of the name Julio and Julius. (For further details on etymology, see the Wiktionary entry "Julius".) The given name ''Julia'' had been in use throughout Late Antiquity (e.g. ...

that facilitates simulations of various kinds of

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 ...

s. It is inspired by the Quantum Optics Toolbox for MATLAB and the Python framework

QuTiP QuTiP, short for the Quantum Toolbox in Python, is an open-source computational physics software library for simulating quantum systems, particularly open quantum systems. QuTiP allows simulation of Hamiltonians with arbitrary time-dependence, ...

. QuantumOptics.jl is being developed in Helmut Ritsch's CQED group at the Institute for Theoretical Physics of the

since 2017, with the 1.0 version being released in July 2021. QuantumOptics.jl remains

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

and is hosted on

GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continuous ...

. There are several Add-Ons related to and/or dependent on QuantumOptics.jl. For example, QuantumCumulants.jl is a package for the symbolic derivation of mean-field equations for quantum mechanical operators in Julia.

Dipole-Dipole interactions

A significant part of his research also involves the investigation of collective effects of atoms with light-induced interactions, including the emergence of superadiance and subradiance in long-range interacting quantum emitters with dipole-dipole interactions.

Honours and awards

* 2019

of the Austrian Academy of Sciences for his outstanding research achievements in the field of

, in particular for his fundamental contributions to the theoretical understanding of light-matter interaction and cavity quantum electrodynamics (CQED). * 2019 JILA visiting fellow award * 2008 Scottish Universities Physics Alliance (SUPA) Distinguished Visitor Award, Glasgow. * 2004 Dr. Otto Seibert Wissenschafts-Förderungs-Preis. * 1993

of the

(jointly with M. Ritsch-Marte). * 1992 Research award of the city of Innsbruck.

External links

Helmut Ritsch
Institut für Theoretische Physik, Universität Innsbruck.

group webpage.
Helmut Ritsch
publications indexed by Google Scholar.

References

{{DEFAULTSORT:Ritsch, Helmut 1962 births Living people People from Innsbruck Quantum physicists Austrian physicists Academic staff of the University of Innsbruck