Practical quantum tokens without quantum memories and experimental tests

Experimental Tests of Quantum Chromodynamics*

Experimental quantum computing without entanglement.

Deterministic quantum computation with one pure qubit (DQC1) is an efficient model of computation that uses highly mixed states. Unlike pure-state models, its power is not derived from the generation of a large amount of entanglement. Instead it has been proposed that other nonclassical correlations are responsible for the computational speedup, and that these can be captured by the quantum dis...

Unforgeable noise-tolerant quantum tokens

The realization of devices that harness the laws of quantum mechanics represents an exciting challenge at the interface of modern technology and fundamental science. An exemplary paragon of the power of such quantum primitives is the concept of “quantum money” [Wiesner S (1983) ACM SIGACT News 15:78–88]. A dishonest holder of a quantum bank note will invariably fail in any counterfeiting attemp...

Quantum Tokens for Digital Signatures

The fisherman caught a quantum fish. Fisherman, please let me go, begged the fish, and I will grant you three wishes. The fisherman agreed. The fish gave the fisherman a quantum computer, three quantum signing tokens and his classical public key. The fish explained: to sign your three wishes, use the tokenized signature scheme on this quantum computer, then show your valid signature to the king...

Practical characterization of quantum devices without tomography.

Quantum tomography is the main method used to assess the quality of quantum information processing devices. However, the amount of resources needed for quantum tomography is exponential in the device size. Part of the problem is that tomography generates much more information than is usually sought. Taking a more targeted approach, we develop schemes that enable (i) estimating the fidelity of a...