Alexei Tsvelik

Alexei Mikhaylovich Tsvelik (Алексей Михайлович Цвелик) is a theoretical condensed matter physicist working on strongly correlated electron systems.

He is widely recognised for his pioneering contributions to the theory of low-dimensional systems, including the applications of quantum field theory and the Bethe Ansatz.

He graduated from the Moscow Physical Technical Institute in 1977,

before gaining his PhD in Theoretical Physics in 1980 from the

Kurchatov Institute for Atomic Energy.

The late 1980s and early 1990s witnessed a concerted experimental and theoretical effort to understand the physics of Haldane gap materials.

Field-theoretical approaches proved useful for this purpose, among which a Landau-Ginzburg approach for the O(3) Non-linear sigma model for large-spin Heisenberg chains, and Tsvelik's conformal field theory approach using a SU_2(2) Wess-Zumino-Novikov-Witten model representable by three critical Majorana fermions.

Separately, Tsvelik also used Majorana fermions to model unusual magnetoresistance properties of high-Tc materials in collaboration with Piers Coleman and Andy Schofield.

Similar approaches proved useful in the understanding of spin ladder materials, of interest as simplified versions of high-Tc materials.

As shown by Tsvelik in collaboration with Nersesyan and Shelton, a two-leg ladder has a simple low-energy representation in terms of four (weakly interacting) massive Majorana fermions, again enabling the calculation of dynamical structure factors.

A recent notable contribution of Tsvelik provides clear pathways in the search for new states of matter in the form of chiral spin liquids.

Between 1982 and 1989 he worked

at the Landau Institute for Theoretical Physics.

After visiting

positions at Harvard, Princeton and the University of Florida, Tsvelik

was appointed as a Lecturer, and subsequently Professor, at the

University of Oxford (where he was affiliated to Brasenose College).

Their 1983 review on exact results on impurity models including Kondo and Anderson impurity models remains a landmark in the use of exact methods in quantum many-body condensed matter.

In 2001 he was appointed as a Senior

Physicist and Group Leader at Brookhaven National Laboratory.

He has also served as an adjunct professor of physics at Stony Brook University.

Tsvelik has published more than 180 papers in refereed journals and is the

author of two textbooks and a third on the philosophy of physics.

Throughout his career, Tsvelik has significantly contributed to the application of quantum field-theoretical methods to the theoretical description of low-dimensional systems, focusing on methods of Integrability, Bosonization and Conformal Field Theory.

Early in his career, he achieved notoriety by solving the multichannel Kondo model using the Bethe Ansatz with Paul Wiegmann.

In 2002 Tsvelik was elected as a Fellow of the American Physical Society with citation For seminal contributions to quantum magnetism and for the exact solutions of important integrable models.

He received a Brookhaven Science and Technology Award in 2006.

In 2009 he was recognized as an Outstanding Referee by the

American Physical Society.

He was awarded a Alexander von Humboldt Research Award in 2014

Tsvelik is a prolific caricaturist renowned among his colleagues for his blend of deference, humour and cynicism.