11 papers · 1 filter
On the entropy of a pseudo-density matrix
James Fullwood, Boyu Yang
The pseudo-density matrix (PDM) formalism naturally extends the notion of density operator to the spatiotemporal domain. While PDMs are Hermitian and of unit trace, they admit nega…
Quantum information loss
James Fullwood, Wu-zhong Guo, Boyu Yang
We introduce a measure of information loss for any quantum process that may be modeled by a prepare-evolve-measure scenario: Alice prepares an ensemble of states that gets sent via…
Operational time-reversal symmetry for unital qubit channels
Ouyang Ting, James Fullwood, Zhen Wu
The Bayesian inverse of a quantum channel is a channel in the reverse direction of that yields time-symmetric correlations for sequential…
On Lorentzian symmetries of quantum information
James Fullwood, Vlatko Vedral, Edgar Guzmán-González
A foundational result in relativistic quantum information theory due to Peres, Scudo, and Terno, is that von Neumann entropy is not Lorentz invariant. Motivated by the "It from Qub…
On Dirac-type correlations
James Fullwood, Boyu Yang
Quantum correlations often defy an explanation in terms of fundamental notions of classical physics, such as causality, locality, and realism. While the mathematical theory underpi…
The Born rule as a natural transformation of functors
Boyu Yang, James Fullwood
In this work, we show that the quantum mechanical notions of density operator, positive operator-valued measure (POVM), and the Born rule, are all simultaneously encoded in the cat…