Mixed quantum states in higher categories

Mixed quantum states in higher categories

There are two ways to describe the interaction between classical and quantum information categorically: one based on completely positive maps between Frobenius algebras, the other using symmetric monoidal 2-categories. This paper makes a first step towards combining the two. The integrated approach allows a unified description of quantum teleportation and classical encryption in a single 2-cate...

Mixed States in Quantum Cryptography

Mixed states are important in quantum computation and quantum information theories. Each quantum mixed state can be described by its density matrix. We discuss how properties of mixed states and their density matrices can be used to explain fundamentals of most popular quantum computing protocols. By using density matrices we show that some of quantum protocols are safe, but some of them allow ...

Quantum Instability for Mixed States

The analysis of the time evolution of unstable states which are linear superposition of other, observable, states can, in principle, be carried out in two distinct, non-equivalent ways. One of the methods, usually employed for the neutral kaon system, combines the mixing and instability into one single step which then results into unconventional properties of the mass-eigenstates. An alternativ...

Minimum-correlation mixed quantum states

We consider states leading to the equality sign in the uncertainty inequalities associated with correlations in open quantum systems which have been recently derived by Ponomarenko and Wolf @Phys. Rev. A 63, 062106 ~2001!#. The new inequalities involve fluctuations defined in terms of the square of the density operator that characterizes mixed states. We find the minimum-correlation states asso...

Higher Operads, Higher Categories