Entanglement, non-Markovianity, and causal non-separability

Abstract

Quantum mechanics, in principle, allows for processes with indefinite causal order. However, most of these causal anomalies have not yet been detected experimentally. We show that every such process can be simulated experimentally by means of non-Markovian dynamics with a measurement on additional degrees of freedom. Explicitly, we provide a constructive scheme to implement arbitrary acausal processes. Furthermore, we give necessary and sufficient conditions for open system dynamics with measurement to yield processes that respect causality locally, and find that tripartite entanglement and nonlocal unitary transformations are crucial requirements for the simulation of causally indefinite processes. These results show a direct connection between three counter-intuitive concepts: non-Markovianity, entanglement, and causal indefiniteness.

arXiv comment14 pages, 8 figures

References in corpus (29)

• Quantum correlations with no causal order
• Quantum computations without definite causal structure
• Theoretical framework for quantum networks
• Quantum Circuits Architecture
• Transforming quantum operations: quantum supermaps
• Non-Markovian quantum processes: complete framework and efficient characterisation
• Experimental Superposition of Orders of Quantum Gates
• Operational Markov condition for quantum processes
• Experimental Verification of an Indefinite Causal Order
• Quantum causal modelling
• Causal and localizable quantum operations
• Witnessing causal nonseparability
• Closed timelike curves via post-selection: theory and experimental demonstration
• On the capacities of bipartite Hamiltonians and unitary gates
• The quantum mechanics of time travel through post-selected teleportation
• The simplest causal inequalities and their violation
• Operational approach to open dynamics and quantifying initial correlations
• On quantum non-signalling boxes
• An introduction to operational quantum dynamics
• Characterizing quantum dynamics with initial system-environment correlations
• Maximal incompatibility of locally classical behavior and global causal order in multi-party scenarios
• A purification postulate for quantum mechanics with indefinite causal order
• The Operator Tensor Formulation of Quantum Theory
• Operational quantum theory without predefined time
• Connecting processes with indefinite causal order and multi-time quantum states
• Bounding quantum correlations with indefinite causal order
• Causally nonseparable processes admitting a causal model
• Optimal Probabilistic Simulation of Quantum Channels from the Future to the Past
• Acausal measurement-based quantum computing

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• Cyclic Quantum Causal Models
• On the definition and characterisation of multipartite causal (non)separability
• Why initial system-environment correlations do not imply the failure of complete positivity: a causal perspective
• Quantum non-Markovianity: Overview and recent developments
• Resource theories of multi-time processes: A window into quantum non-Markovianity
• Genuine Multipartite Entanglement in Time
• Diagrammatic method for many-body non-Markovian dynamics: memory effects and entanglement transitions
• Non-Markovian Memory Strength Bounds Quantum Process Recoverability
• Simple and maximally robust processes with no classical common-cause or direct-cause explanation
• Quantum causal correlations and non-Markovianity of quantum evolution
• Necessary and Sufficient Conditions on Measurements of Quantum Channels
• Memory Effects in Quantum Processes
• Activating information backflow with the assistance of quantum SWITCH
• Correlation Measure Equivalence in Dynamic Causal Structures of Quantum Gravity
• Theory of Quantum Gravity Information Processing
• Universal construction of decoders from encoding black boxes
• Quantum chicken-egg dilemmas: Delayed-choice causal order and the reality of causal non-separability
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• Relations between Markovian and non-Markovian correlations in multitime quantum processes
• How Deep the Theory of Quantum Communications Goes: Superadditivity, Superactivation and Causal Activation
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• Fermionic duality: General symmetry of open systems with strong dissipation and memory
• Simulating the quantum switch with quantum circuits is computationally hard
• Causal nonseparability and its implications for spatiotemporal relations
• Quantum walks under superposition of causal order