Evaluating the advantage of adaptive strategies for quantum channel distinguishability

Quantum machine learning channel discrimination

“…Remarkably, training such a quantum classifier with a simpler and less expressive ansatz is advantageous. In principle, the circuit of 7 parameters U 1 defined in (22) is capable of preparing any pure two-qubit state, showing yet worse performance compared to the one trained with the ansatz U 2 in (23) containing no entangling gates. We tried to add a CX gate to this circuit, which increases its expressive power without introducing any optimization parameters.…”

“…In particular, it is expected that quantum channels can be discriminated more efficiently if it is allowed to apply a given channel several times. For different channels and discrimination strategies, the efficiency of discrimination as well as the associated quantitative measures have previously been considered [16][17][18][19][20][21][22][23]. Of particular interest and technological relevance [24] are the parallel and sequential strategies [24].…”

“…As a rule, the sequential strategy, incarnating the idea of quantum comb [5,58], provides better discrimination results compared to the parallel strategy [22,23]. Meanwhile, it is worth mentioning a more general discrimination strategy that is based on the so-called indefinite casual order of channel application [15].…”

Coherence requirements for quantum communication from hybrid circuit dynamics

“…For example, entanglement and coherence have been demonstrated as essential resources for performing quantum sensing [12,16,17]. At the same time, any resource for any given quantum resource theory is useful in some channel discrimination task [18][19][20][21][22][23][24]. Finally, Ref.…”

A coherence-theoretic analysis of quantum neural networks

“…It is expected that, adding to the parallel processing properties of NNs quantum features like correlations, entanglement and superposition, should result in an enhancement of their performances [10][11][12]. Crucially, coherence, i.e., the amount of superposition displayed by a quantum state, plays a relevant role in quantum thermodynamics [13][14][15], quantum channel discrimination [16][17][18], quantum biology [19], etc., and can be cast, therefore, within the framework of a quantum resource theory [20]. Interestingly, the CPTP maps possessing the maximal number of stationary states correspond to noncoherence-generating operations.…”