Popular summaries

Absolutely maximally entangled pure states of multipartite quantum systems

Quantum Advantage in Identifying the Parity of Permutations with Certainty

Quantum technologies allow for possibilities beyond than their classical counterpart. This is the core concept of quantum advantage, which manifests itself in phenomena that can occur in a quantum mechanical description of nature but not in a classical description. In this work we show that quantum advantage appears in the answer of a very simple question: you are given n objects with certain distinguished labels, and we swap them pairwise in a way in a way that you cannot see. By looking at the labels only once, can you tell how many swaps did we make? If the objects are classical, n distinct labels are needed. The main result of this work is that if the objects are entangled particles, then the problem can be solved with less system dimensions (i.e. quantum labels). Our work has attracted the atention of the Outreach Journal Phys.org, which described it in an accessible way in This featured article.

Certifying nonlocal properties of noisy quantum operations

Quantum operations determine the evolution of quantum systems. Operations acting on bipartite systems induce the nonlocal defining properties inherent to quantum mechanics. Therefore, it is crucial to understand the non-local features of quantum operations, which account for their nonlocal capabilities. Here we reveal such properties from the probability of detector clicks, conditional to input state preparations that can be determined by classical means like coin-tossing. We examine in detail the effects of noise in such detection methods, and find extremal phenomena in principle allowed by the most general theory of dephasing. Finally, we focus on the completely decoherent case, where only classical state preparations and measurements can effectively be done. In such case, states are mapped to probabilities and channels to conditional distributions. In this scenario, we still reveal the full structure of nonlocality in channels by local preparation-measurements in the computational basis.

Mixed state entanglement from symmetric matrix inequalities

State-witness contraction

Discrete dynamics in the set of quantum measurements

Channel nonlocality under decoherence

Entanglement detection with trace polynomials