Constantino Tsallis (; el, Κωνσταντίνος Τσάλλης ; born 4 November 1943) is a naturalized

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

ian

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 ca ...

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

descent, working in

Rio de Janeiro Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the Rio de Janeiro (state), state of the same name, Brazil's List of Brazilian states by population, third-most populous state, and the List of largest citi ...

at Centro Brasileiro de Pesquisas Físicas (CBPF),

Biography

Tsallis was born in

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders wit ...

, and grew up in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

, where he studied physics at Instituto Balseiro, in

Bariloche San Carlos de Bariloche, usually known as Bariloche (), is a city in the province of Río Negro, Argentina, situated in the foothills of the Andes on the southern shores of Nahuel Huapi Lake. It is located within the Nahuel Huapi National Par ...

. In 1974, he received a ''Doctorat d'État ès Sciences Physiques'' degree from the

University of Paris-Sud Paris-Sud University (French: ''Université Paris-Sud''), also known as University of Paris — XI (or as Université d'Orsay before 1971), was a French research university distributed among several campuses in the southern suburbs of Paris, in ...

. He moved to Brazil in 1975 with his wife and daughter. Tsallis is an External Professor of the

Santa Fe Institute The Santa Fe Institute (SFI) is an independent, nonprofit theoretical research institute located in Santa Fe, New Mexico, United States and dedicated to the multidisciplinary study of the fundamental principles of complex adaptive systems, inclu ...

. In 2011 he gave a talk ''From Nonlinear Statistical Mechanics to Nonlinear Quantum Mechanics — Concepts and Applications'' at the international symposium on subnuclear physics held in Vatican City.

Research

Tsallis is credited with introducing the notion of what is known as

Tsallis entropy In physics, the Tsallis entropy is a generalization of the standard Boltzmann–Gibbs entropy. Overview The concept was introduced in 1988 by Constantino Tsallis as a basis for generalizing the standard statistical mechanics and is identical in f ...

and

Tsallis statistics The term Tsallis statistics usually refers to the collection of mathematical functions and associated probability distributions that were originated by Constantino Tsallis. Using that collection, it is possible to derive Tsallis distributions from ...

in his 1988 paper "Possible generalization of Boltzmann–Gibbs statistics" published in the ''

Journal of Statistical Physics The ''Journal of Statistical Physics'' is a biweekly publication containing both original and review papers, including book reviews. All areas of statistical physics as well as related fields concerned with collective phenomena in physical systems ...

''. The generalization is considered to be a good candidate for formulating a theory of non- extensive

thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws o ...

. The resulting theory is not intended to replace Boltzmann–Gibbs statistics, but rather supplement it, such as in the case of anomalous systems characterised by non-ergodicity or

metastable state In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system's state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. If the ball ...

s. One experimental verification of the predictions of

concerned cold atoms in dissipative

optical lattice An optical lattice is formed by the interference of counter-propagating laser beams, creating a spatially periodic polarization pattern. The resulting periodic potential may trap neutral atoms via the Stark shift. Atoms are cooled and congreg ...

s. Eric Lutz mad
an analytical prediction
in 2003 which was verified in 2006 by
a London team
Tsallis conjectured in 1999
''Brazilian Journal of Physics'' 29, 1
Figure 4): #That a longstanding quasi-stationary state (QSS) was expected in long-range interacting

Hamiltonian system A Hamiltonian system is a dynamical system governed by Hamilton's equations. In physics, this dynamical system describes the evolution of a physical system such as a planetary system or an electron in an electromagnetic field. These systems can ...

s (one of the core problems of statistical mechanics). This was verified by groups around the world. #That this QSS should be described by Tsallis statistics instead of Boltzmann–Gibbs statistics. This was verified in June 2007 by
Pluchino, Rapisarda and Tsallis
(in the last figure, instead of the Maxwellian (Gaussian) distribution of velocities (valid for short-range interactions), one sees a

q-Gaussian The ''q''-Gaussian is a probability distribution arising from the maximization of the Tsallis entropy under appropriate constraints. It is one example of a Tsallis distribution. The ''q''-Gaussian is a generalization of the Gaussian in the sam ...

References

External links

Homepage of Constantino Tsallis

{{DEFAULTSORT:Tsallis, Constantino Greek emigrants to Brazil Argentine people of Greek descent 1943 births Living people Brazilian physicists Members of the Brazilian Academy of Sciences Naturalized citizens of Brazil Commanders of the National Order of Scientific Merit (Brazil) Santa Fe Institute people National University of Cuyo alumni University of Paris alumni 20th-century Brazilian physicists