Probabilistic theories with purification
We investigate general probabilistic theories in which every mixed state has a purification, unique up to reversible channels on the purifying system. We show that the purification principle is…
Theoretical framework for quantum networks
We present a framework to treat quantum networks and all possible transformations thereof, including as special cases all possible manipulations of quantum states, measurements, and channels, such…
Informational derivation of quantum theory
We derive quantum theory from purely informational principles. Five elementary axioms - causality, perfect distinguishability, ideal compression, local distinguishability, and pure conditioning -…
Quantum computations without definite causal structure
It is shown that quantum theory allows for transformations of black boxes that cannot be realized by inserting the input black boxes within a circuit in a pre-defined causal order, and that the quantum version of this transformation-the quantum switch- produces an output circuit where the order of the connections is controlled by a quantum bit, which becomes entangled with the circuit structure.
Transforming quantum operations: Quantum supermaps
We introduce the concept of quantum supermap, describing the most general transformation that maps an input quantum operation into an output quantum operation. Since quantum operations include as…
Enhanced Communication with the Assistance of Indefinite Causal Order.
This Letter shows that two identical copies of a completely depolarizing channel become able to transmit information when they are combined in a quantum superposition of two alternative orders, counter to the intuition that if two communication channels are identical, using them in different orders should not make any difference.
Quantum circuit architecture.
- G. Chiribella, G. D’Ariano, P. Perinotti
- Physics, Computer SciencePhysical Review Letters
- 9 December 2007
Unexplored quantum processing tasks, such as cloning and storing or retrieving of gates, can be optimized, along with setups for tomography and discrimination or estimation of quantum circuits.
Quantum Shannon theory with superpositions of trajectories
This work proposes a second level of quantization where both the information and its propagation in space–time is treated quantum mechanically.
Indefinite causal order enables perfect quantum communication with zero capacity channels
Quantum mechanics is compatible with scenarios where the relative order between two events can be indefinite. Here we show that two independent instances of a noisy process can behave as a perfect…
Perfect discrimination of no-signalling channels via quantum superposition of causal structures
- G. Chiribella
- Philosophy, Computer Science
- 23 September 2011
It is proved that two no-signalling channels that are not perfectly distinguishable in any ordinary quantum circuit can become perfectly distinguishability through the quantum superposition of circuits with different causal structures.