Rolf Gohm

Linear quantum feedback networks

Gough, J. E., Gohm, R., Yanagisawa, M. (2008). Linear quantum feedback networks. Physical Review A, 78 (6), Article No: 062104.

Characteristic Functions of Liftings

We introduce characteristic functions for certain contractive liftings of row contractions. These are multi-analytic operators which classify the liftings up to unitary equivalence and provide a kind of functional model. The most important cases are subisometric and coisometric liftings. We also identify the most general setting which we call reduced liftings. We derive properties of these new characteristic functions and discuss the relation to Popescus definition for completely non-coisometric row contractions. Finally we apply our theory to completely positive maps and prove a one-to-one correspondence between the fixed point sets of completely positive maps related to each other by a subisometric lifting.

Noncommutative Independence from the Braid Group B

We introduce ‘braidability’ as a new symmetry for infinite sequences of noncommutative random variables related to representations of the braid group

Noncommutative Independence from the Braid Group \({\mathbb{B}_{\infty}}\)

{\mathbb{B}_{\infty}}

KÜMMERER–MAASSEN-SCATTERING THEORY AND ENTANGLEMENT

. It provides an extension of exchangeability which is tied to the symmetric group

Semi-cosimplicial objects and spreadability

{\mathbb{S}_{\infty}}