3 papers
quant-ph2026
Existence of Kraus decomposition in infinite dimension via strongly-convergent direct process tomography
Paul E. Lammert
An algorithm is presented for Kraus decomposition of a completely positive operator over separable (countably-infinite-dimensional) Hilbert spaces, together with an elementary proo…
quant-ph2026
Notes on completely positive maps and continuous-time Markovian CP evolution. A geometry-flavored perspective
Paul E. Lammert
These notes provide a detailed and self-contained exposition of basic theory of CP maps and continuous-time Markovian evolution.The infinite-dimensional (separable) setting is hand…
cond-mat.stat-mech2025
Classical triangular lattice antiferromagnetic Ising model as a free-fermion/superconductor system
Amir Nourhani, Vincent H. Crespi, Paul E. Lammert
We present a treatment of the triangular lattice antiferromagnetic Ising model (TAFIM) based on a small number of elementary ideas common to statistical and solid-state physics. Th…