Lorenzo M. Procopio

TL;DR: This work experimentally demonstrates the creation of the required superposition of gate orders by using additional degrees of freedom of the photons encoding qubits, which could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer.

TL;DR: Researchers report the first decisive demonstration of a process with an indefinite causal order, and experimentally determine a causal witness, demonstrating by almost 7 SDs that the experimentally implemented process does not have a definite causal order.

TL;DR: The quantum 3-switch is introduced as a resource for quantum communications and performs a new kind of quantum control that was not accessible to the previously treated two-channel case, allowing for non monotonous behavior on the transmission of information with respect to the number of causal orders involved.

TL;DR: In this paper, the authors proposed a formalism to assess information transmission in the most general case of N channels in an indefinite causal order scenario yielding the output of such transmission, and explicitly derived the quantum switch output and the associated Holevo limit of the information transmission for N = 2, N = 3 as a function of all involved parameters.

TL;DR: A formalism to assess information transmission in the most general case of N channels in an indefinite causal order scenario yielding the output of such transmission is proposed and it is found that the transmission of information for three channels is twice that of transmission of the two-channel case when a full superposition of all possible causal orders is used.