Entanglement witnesses provide an efficient means of determining the level of entanglement of a system using the minimum number of measurements. Here we demonstrate the observation of twodimensional entanglement witnesses in the high-dimensional basis of orbital angular momentum (OAM). In this case, the number of potentially entangled subspaces scales as d(d− 1)/2, where d is the dimension of t...

Quantum information is mostly based on use of entanglement, and optimal performances of quantum protocols are obtained when the parties share maximally entangled states. However, entanglement is corrupted by the interaction with the environment, and it becomes crucial to establish whether or not quantum protocols may be exploited for a given level of the environmental noise. Quantum purificatio...

Quantum-mechanical systems can be used for real-world applications of significant importance, including quantum information processing [1,2], quantum cryptography [3], and quantum metrology [4]. Many of these applications require entanglement between more than two parties; see, e.g., [1,2]. Such systems also allow us to probe the transition from quantum to classical behaviors in increasingly co...

We compare the evolution of entanglement for a system of two two-level atoms interacting with (i) a common reservoir being in the vacuum state and (ii) a common thermal reservoir at non-zero temperature. The Markovian master equation is used to describe the evolution of entanglement which is quantified by concurrence. Phenomena of sudden death, revival, and sudden birth of entanglement are disc...

We study the evolution of entanglement and nonlocality of a non-interacting qubit-qutrit system under the effect of random telegraph noise (RTN) in independent and common environments in Markovian and non-Markovian regimes. We investigate the dynamics of qubit-qutrit system for different initial states. These systems could be existed in far astronomical objects. A monotone decay of the nonlocalit...

Computations in a distributed environment comprising a network of spatially separated nodes may require the exchange of classical and quantum information. The amount of classical communication may be reduced in such computations by using multipartite entanglement. Following the combinatorial approach developed in [25, 27], we study entanglement configurations over a set of nodes, where each ent...

Entanglement is a parameter for the complexity of finite directed graphs that measures to which extent the cycles of the graph are intertwined. It is defined by way of a game similar in spirit to the cops and robber games used to describe tree width, directed tree width, and hypertree width. Nevertheless, on many classes of graphs, there are significant differences between entanglement and the ...

In this paper we study bipartite quantum correlations using techniques from tracial polynomial optimization. We construct a hierarchy of semidefinite programming lower bounds on the minimal entanglement dimension of a bipartite correlation. This hierarchy converges to a new parameter: the minimal average entanglement dimension, which measures the amount of entanglement needed to reproduce a qua...