5 papers · 1 filter
Characterizing unitaries via quasi-process functions
Nasra Daher Ahmed, Ravi Kunjwal
It is well-known that every n-qubit unitary can be decomposed into a product of controlled single-qubit unitaries. We show that the control conditions in such a decomposition natur…
Causal inequalities witness non-stabilizerness
Leonardo Vaglini, Nasra Daher Ahmed, Ravi Kunjwal
Stabilizer operations describe a fragment of quantum theory that is known to be efficiently classically simulable, thanks to the Gottesman-Knill theorem. For this reason, nonstabil…
What makes a causal loop consistent?
Hippolyte Dourdent, Andreas Leitherer, Emanuel-Cristian Boghiu +3
Causal loops escape paradoxes if they generate valid probabilities under arbitrary independent local interventions. We show that a deterministic classical process is logically cons…
Indefinite Causal Order Reverses the Real-Complex Hierarchy
Jacopo Surace, Shintaro Minagawa, Ravi Kunjwal
[Note added after submission. After posting the first version of this preprint and corresponding with Ved Kunte and Kuntal Sengupta, we identified an issue with the claimed separat…
All star-incompatible measurements can certify steering-based randomness
Shintaro Minagawa, Ravi Kunjwal
Certifying that quantum randomness generated by untrusted devices is unpredictable to an attacker (say, Eve) is crucial for device-independent security. Bipartite protocols where o…