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

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

[12] As shown by Tsvelik in collaboration with Nersesyan and Shelton,[13] a two-leg ladder has a simple low-energy representation in terms of four (weakly interacting) massive Majorana fermions, enabling the calculation of dynamical structure factors.

[15] In 2002 Tsvelik was elected as a Fellow[16] of the American Physical Society[17] with citation For seminal contributions to quantum magnetism and for the exact solutions of important integrable models.

Alexei Tsvelik, in co-authorship with Alexey Burov [ru], published a series of metaphysical articles "Pythagorean Argument of the Intelligent Design of the Universe and its Critique", in the Russian journal "Ideas and Ideals".