We consider the certification of temporal quantum correlations using the pseudo-density
operator (PDO), an extension of the density matrix to the time domain, where negative …

From correlations in measurement outcomes alone, can two otherwise isolated parties
establish whether such correlations are atemporal? That is, can they rule out that they have …

The quantum no-broadcasting theorem states that it is impossible to produce perfect copies
of an arbitrary quantum state, even if the copies are allowed to be correlated. Here we show …

We consider how to tell the time-ordering associated with measurement data from quantum
experiments at two times and any number of qubits. We define an arrow of time inference …

We consider the relation between three different approaches to defining quantum states
across several times and locations: the pseudo-density matrix (PDM), the process matrix …

Spatial and temporal quantum correlations can be unified in the framework of the pseudo-
density operators (PDOs), and quantum causality between the involved events in an …

While in relativity theory space evolves over time into a single entity known as spacetime,
quantum theory lacks a standard notion of how to encapsulate the dynamical evolution of a …

The measurement statistics for spatial and temporal quantum processes are produced
through distinct mechanisms. Measurements that are space‐like separated exhibit non …

Two-time expectation values of sequential measurements of dichotomic observables are
known to be time symmetric for closed quantum systems. Namely, if a system evolves …

In this work, we use the theory of quantum states over time to define an entropy $ S
(\rho,\mathcal {E}) $ associated with quantum processes $(\rho,\mathcal {E}) $, where $\rho …