Theory-independent monitoring of the decoherence of a superconducting qubit with generalized contextuality
arXiv:2411.13421 · doi:10.1038/s41467-026-69030-x
Abstract
Characterizing the nonclassicality of quantum systems under minimal assumptions is an important challenge for quantum foundations and technology. Here we introduce a theory-independent method of process tomography and perform it on a superconducting qubit. We demonstrate its decoherence without assuming quantum theory or trusting the devices by modelling the system as a general probabilistic theory. We show that the superconducting system is initially well-described as a quantum bit, but that its realized state space contracts over time, which in quantum terminology indicates its loss of coherence. The system is initially nonclassical in the sense of generalized contextuality: it does not admit of a hidden-variable model where statistically indistinguishable preparations are represented by identical hidden-variable distributions. In finite time, the system becomes noncontextual and hence loses its nonclassicality. Moreover, we demonstrate in a theory-independent way that the system undergoes non-Markovian evolution at late times. Our results extend theory-independent tomography to time-evolving systems, and show how important dynamical physical phenomena can be experimentally monitored without assuming quantum theory.
arXiv comment17 pages, 10 figures. V2: close to published version
References in corpus (44)
- Charge insensitive qubit design derived from the Cooper pair box
- Experimental loophole-free violation of a Bell inequality using entangled electron spins separated by 1.3 km
- Circuit Quantum Electrodynamics
- Significant-loophole-free test of Bell's theorem with entangled photons
- Superconducting Qubits: Current State of Play
- A strong loophole-free test of local realism
- Contextuality for preparations, transformations, and unsharp measurements
- Informational derivation of Quantum Theory
- Instantaneous non-local computation of low T-depth quantum circuits
- The Heisenberg Representation of Quantum Computers
- Measurement of areas on a sphere using Fibonacci and latitude-longitude lattices
- Quantum Theory From Five Reasonable Axioms
- Probabilistic theories with purification
- The Moore-Penrose Pseudoinverse. A Tutorial Review of the Theory
- Concepts of quantum non-Markovianity: a hierarchy
- A derivation of quantum theory from physical requirements
- Negativity and contextuality are equivalent notions of nonclassicality
- Bell Correlations in a Bose-Einstein Condensate
- An experimental test of noncontextuality without unwarranted idealizations
- Preparation contextuality powers parity-oblivious multiplexing
- Finite precision measurement nullifies the Kochen-Specker theorem
- Maximal violation of the I3322 inequality using infinite dimensional quantum systems
- Low-Rank Matrix Approximation with Weights or Missing Data is NP-hard
- Generalized Probability Theories: What determines the structure of quantum theory?
- Higher-order interference and single-system postulates characterizing quantum theory
- General probabilistic theories: An introduction
- The Characterization of Noncontextuality in the Framework of Generalized Probabilistic Theories
- Contextuality without nonlocality in a superconducting quantum system
- Three Slit Experiments and the Structure of Quantum Theory
- Experimentally bounding deviations from quantum theory in the landscape of generalized probabilistic theories
- Uniqueness of noncontextual models for stabilizer subtheories
- Communication games reveal preparation contextuality
- Preparation contextuality as an essential feature underlying quantum communication advantage
- Entanglement is an inevitable feature of any non-classical theory
- Entanglement is necessary for emergent classicality in all physical theories
- Why initial system-environment correlations do not imply the failure of complete positivity: a causal perspective
- Deriving robust noncontextuality inequalities from algebraic proofs of the Kochen-Specker theorem: the Peres-Mermin square
- A structure theorem for generalized-noncontextual ontological models
- Contextuality and The Single-Qubit Stabilizer Formalism
- Experimentally bounding deviations from quantum theory for a photonic three-level system using theory-agnostic tomography
- Solvable Criterion for the Contextuality of any Prepare-and-Measure Scenario
- A linear program for testing nonclassicality and an open-source implementation
- A mathematical framework for operational fine tunings
- Resource-theoretic hierarchy of contextuality for general probabilistic theories