suvrajib

• Bhattacharjee, Suvrajit & Forough, Marzieh (2025). Quasi-invariant lifts of completely positive maps for groupoid actions. Mathematical proceedings of the Cambridge Philosophical Society (Print). ISSN 0305-0041. 180(1), p. 35–63. doi: 10.1017/S0305004125101436. Full text in Research Archive
• Bhattacharjee, Suvrajit; Joardar, Soumalya & Roy, Sutanu (2024). Braided quantum symmetries of graph C*-algebras. International Journal of Mathematics. ISSN 0129-167X. 35(13). doi: 10.1142/S0129167X24500514. Full text in Research Archive Show summary

  We prove the existence of a universal braided compact quantum group acting on a graph C∗-algebra in the category of T-C∗-algebras with a twisted monoidal structure, in the spirit of the seminal work of Wang. To achieve this, we construct a braided analogue of the free unitary quantum group and study its bosonization. As a concrete example, we compute this universal braided compact quantum group for the Cuntz algebra.

• Bhattacharjee, Suvrajit & Joardar, Soumalya (2023). Equivariant C∗-correspondences and compact quantum group actions on Pimsner algebras. Canadian Journal of Mathematics (CJM). ISSN 0008-414X. doi: 10.4153/S0008414X23000810. Full text in Research Archive Show summary

  Let G be a compact quantum group. We show that given a G-equivariant C∗-correspondence E, the Pimsner algebra OE can be naturally made into a G-C∗-algebra. We also provide sufficient conditions under which it is guaranteed that a G-action on the Pimsner algebra OE arises in this way, in a suitable precise sense. When G is of Kac type, a KMS state on the Pimsner algebra, arising from a quasi-free dynamics, is G-equivariant if and only if the tracial state obtained from restricting it to the coefficient algebra is G-equivariant, under a natural condition. We apply these results to the situation when the C∗-correspondence is obtained from a finite, directed graph and draw various conclusions on the quantum automorphism groups of such graphs, both in the sense of Banica and Bichon.

• Anshu, NN; Bhattacharjee, Suvrajit; Rahaman, Atibur & Roy, Sutanu (2023). Anyonic quantum symmetries of finite spaces. Letters in Mathematical Physics. ISSN 0377-9017. 113(6). doi: 10.1007/s11005-023-01736-1. Full text in Research Archive

View all works in NVA

• Bhattacharjee, Suvrajit (2024). Crystallization and K-theoretical aspects of the quantum twistor bundle. Full text in Research Archive
• Bhattacharjee, Suvrajit (2024). Braided quantum groups and their actions. Full text in Research Archive
• Bhattacharjee, Suvrajit (2023). Equivariant lifting problem for continuous fields of completely positive maps. Full text in Research Archive

View all works in NVA