TY - RPRT T1 - On the gauge group of Galois objects Y1 - 2020 A1 - Xiao Han A1 - Giovanni Landi AB - We study the Ehresmann--Schauenburg bialgebroid of a noncommutative principal bundle as a quantization of the classical gauge groupoid of a principal bundle. When the base algebra is in the centre of the total space algebra, the gauge group of the noncommutative principal bundle is isomorphic to the group of bisections of the bialgebroid. In particular we consider Galois objects (non-trivial noncommutative bundles over a point in a sense) for which the bialgebroid is a Hopf algebra. For these we give a crossed module structure for the bisections and the automorphisms of the bialgebroid. Examples include Galois objects of group Hopf algebras and of Taft algebras. UR - https://arxiv.org/abs/2002.06097 ER - TY - JOUR T1 - The Gysin sequence for quantum lens spaces JF - Journal of Noncommutative Geometry Y1 - 2016 A1 - Francesca Arici A1 - Simon Brain A1 - Giovanni Landi AB -

We define quantum lens spaces as ‘direct sums of line bundles’ and exhibit them as ‘total spaces’ of certain principal bundles over quantum projective spaces. For each of these quantum lens spaces we construct an analogue of the classical Gysin sequence in K-theory. We use the sequence to compute the K-theory of the quantum lens spaces, in particular to give explicit geometric representatives of their K-theory classes. These representatives are interpreted as ‘line bundles’ over quantum lens spaces and generically define ‘torsion classes’. We work out explicit examples of these classes.

VL - 9 ER - TY - JOUR T1 - Gauged Laplacians on quantum Hopf bundles JF - Comm. Math. Phys. 287 (2009) 179-209 Y1 - 2009 A1 - Giovanni Landi A1 - Cesare Reina A1 - Alessandro Zampini AB - We study gauged Laplacian operators on line bundles on a quantum 2-dimensional sphere. Symmetry under the (co)-action of a quantum group allows for their complete diagonalization. These operators describe `excitations moving on the quantum sphere\\\' in the field of a magnetic monopole. The energies are not invariant under the exchange monopole/antimonopole, that is under inverting the direction of the magnetic field. There are potential applications to models of quantum Hall effect. PB - Springer UR - http://hdl.handle.net/1963/3540 U1 - 1161 U2 - Mathematics U3 - Mathematical Physics ER - TY - JOUR T1 - Graded Chern-Simons terms JF - Phys. Lett. B 192 (1987), no. 1-2, 81-88. Y1 - 1987 A1 - Giovanni Landi A1 - Giuseppe Marmo PB - SISSA Library UR - http://hdl.handle.net/1963/508 U1 - 3396 U2 - Mathematics U3 - Mathematical Physics ER -