Reassessing thermodynamic advantage from indefinite causal order

Abstract

Indefinite causal order is a key feature involved in the study of quantum higher order transformations. Recently, intense research has been focused on possible advantages related to the lack of definite causal order of quantum processes. Quite often the quantum switch is claimed to provide advantages in information-theoretic and thermodynamic tasks. We address here the question whether indefinite causal order is a resource for quantum thermodynamics. Inspired by previous results in the literature, we show that indefinite causal order is not necessary for the reported increase in free energy and ergotropy. More specifically, we show that a simple causally ordered process, which replaces the system's state with a new one before the final measurement, outperforms the quantum switch in all thermodynamic tasks considered so far. We further show that a similar advantage can be also achieved without completely discarding system, if we allow for non-Markovian interactions between the system and an environment. We extend the analysis to more extreme examples of indefinite causal order, showing that they do not provide an advantage either. Finally, we discuss a possible way to study the advantages that may arise from indefinite causal order in a general scenario.

References in corpus (77)

• Fundamental limitations for quantum and nano thermodynamics
• Quantum correlations with no causal order
• The Resource Theory of Quantum States Out of Thermal Equilibrium
• Maximal work extraction from quantum systems
• Quantum computations without definite causal structure
• Transforming quantum operations: quantum supermaps
• Non-Markovian quantum processes: complete framework and efficient characterisation
• Experimental Superposition of Orders of Quantum Gates
• Computational advantage from quantum-controlled ordering of gates
• Operational Markov condition for quantum processes
• Experimental Verification of an Indefinite Causal Order
• Quantum causal modelling
• Enhanced communication with the assistance of indefinite causal order
• Perfect discrimination of no-signalling channels via quantum superposition of causal structures
• Indefinite Causal Order in a Quantum Switch
• Towards Quantum Gravity: A Framework for Probabilistic Theories with Non-Fixed Causal Structure
• Exponential Communication Complexity Advantage from Quantum Superposition of the Direction of Communication
• Witnessing causal nonseparability
• Quantum stochastic processes and quantum non-Markovian phenomena
• Daemonic Ergotropy: Enhanced Work Extraction from Quantum Correlations
• Quantum Metrology with Indefinite Causal Order
• Demonstration of non-Markovian process characterisation and control on a quantum processor
• Causal and causally separable processes
• Experimental transmission of quantum information using a superposition of causal orders
• Experimental Quantum Switching for Exponentially Superior Quantum Communication Complexity
• Comparison of Quantum Channels by Superchannels
• Quantum superposition of the order of parties as a communication resource
• Bell's Theorem for Temporal Order
• Quantum Refrigeration with Indefinite Causal Order
• Indefinite causal order enables perfect quantum communication with zero capacity channels
• Experimental Quantum Communication Enhancement by Superposing Trajectories
• Non-Markovian Quantum Process Tomography
• Communication through coherent control of quantum channels
• Repeated interactions and quantum stochastic thermodynamics at strong coupling
• Reversing Unknown Quantum Transformations: Universal Quantum Circuit for Inverting General Unitary Operations
• Simulation complexity of open quantum dynamics: Connection with tensor networks
• Communication through quantum-controlled noise
• An introduction to operational quantum dynamics
• Characterizing quantum dynamics with initial system-environment correlations
• Kolmogorov extension theorem for (quantum) causal modelling and general probabilistic theories
• Resource theories of communication
• Sending classical information via three noisy channels in superposition of causal orders
• A purification postulate for quantum mechanics with indefinite causal order
• An operational approach to quantum stochastic thermodynamics
• Quantum circuits with classical versus quantum control of causal order
• The space of logically consistent classical processes without causal order
• Noisy quantum metrology with the assistance of indefinite causal order
• Work extraction from coherently activated maps via quantum switch
• Channel capacity enhancement with indefinite causal order
• Updating the Born rule
• Quantum computation with indefinite causal structures
• Operational quantum theory without predefined time
• Unruh-deWitt detectors in quantum superpositions of trajectories
• Thermodynamic Capacity of Quantum Processes
• Thermodynamic advancement in the causally inseparable occurrence of thermal maps
• Experiments on quantum causality
• Witnesses of causal nonseparability: an introduction and a few case studies
• Witnessing quantum memory in non-Markovian processes
• Thermal devices powered by generalized measurements with indefinite causal order
• Deterministic transformations between unitary operations: Exponential advantage with adaptive quantum circuits and the power of indefinite causality
• Causation does not explain contextuality
• Thermodynamics of quantum switch information capacity activation
• Causal order as a resource for quantum communication
• Thermodynamics of Quantum Causal Models: An Inclusive, Hamiltonian Approach
• Noncausal Page-Wootters circuits
• Quantum Markovianity as a supervised learning task
• Semi-device-independent certification of indefinite causal order in a photonic quantum switch
• Thermality, causality and the quantum-controlled Unruh-deWitt detector
• Reversible time travel with freedom of choice
• Reversible dynamics with closed time-like curves and freedom of choice
• Quantum superpositions of causal orders as an operational resource
• Thermodynamic Implementations of Quantum Processes
• Classical communication through quantum causal structures
• Breaking the limits of purification: Postselection enhances heat-bath algorithmic cooling
• Quantum chicken-egg dilemmas: Delayed-choice causal order and the reality of causal non-separability
• Quantum from principles without assuming definite causal structure
• Background Independence and Quantum Causal Structure

Cited by in corpus (7)

• Experimental Aspects of Indefinite Causal Order in Quantum Mechanics
• Reassessing the advantage of indefinite causal orders for quantum metrology
• Experimental Validation of Enhanced Information Capacity by Quantum Switch in Accordance with Thermodynamic Laws
• Quantum switch instabilities with an open control
• Expressibility, entangling power and quantum average causal effect for causally indefinite circuits
• Thermodynamic criteria for signaling in quantum channels
• Operational models of temperature superpositions