Giving Operational Meaning to the Superposition of Causal Orders
- URL: http://arxiv.org/abs/2003.13306v2
- Date: Mon, 6 Sep 2021 12:16:31 GMT
- Title: Giving Operational Meaning to the Superposition of Causal Orders
- Authors: Nicola Pinzani (University of Oxford), Stefano Gogioso (University of
Oxford)
- Abstract summary: This work fits within a recent effort to understand how the standard operational perspective on quantum theory could be extended to indefinite causality.
We investigate how the concept of indefiniteness emerges from specific characteristics of generic operational theories.
To validate our framework, we show how salient examples from the literature can be captured in our framework.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: In this work, we give rigorous operational meaning to superposition of causal
orders. This fits within a recent effort to understand how the standard
operational perspective on quantum theory could be extended to include
indefinite causality. The mainstream view, that of "process matrices", takes a
top-down approach to the problem, considering all causal correlations that are
compatible with local quantum experiments. Conversely, we pursue a bottom-up
approach, investigating how the concept of indefiniteness emerges from specific
characteristics of generic operational theories. Specifically, we pin down the
operational phenomenology of the notion of non-classical (e.g. "coherent")
control, which we then use to formalise a theory-independent notion of control
(e.g. "superposition") of causal orders. To validate our framework, we show how
salient examples from the literature can be captured in our framework.
Related papers
- Relaxation of first-class constraints and the quantization of gauge
theories: from "matter without matter" to the reappearance of time in quantum
gravity [75.38606213726906]
First-class phase-space constraints may be relaxed if we interpret them as fixing the values of new degrees of freedom.
This idea goes back to Fock and Stueckelberg, leading to restrictions of the gauge symmetry of a theory.
In particular, in the case of canonical quantum gravity, the Fock--Stueckelberg approach is relevant to the so-called problem of time.
arXiv Detail & Related papers (2024-02-19T19:00:02Z) - A Measure-Theoretic Axiomatisation of Causality [55.6970314129444]
We argue in favour of taking Kolmogorov's measure-theoretic axiomatisation of probability as the starting point towards an axiomatisation of causality.
Our proposed framework is rigorously grounded in measure theory, but it also sheds light on long-standing limitations of existing frameworks.
arXiv Detail & Related papers (2023-05-19T13:15:48Z) - Noncausal Page-Wootters circuits [0.0]
Page-Wootters formalism associates to time a Hilbert space structure similar to spatial position.
By explicitly introducing a quantum clock, it allows to describe time-evolution of systems via correlations between this clock and said systems encoded in history states.
We describe how to extract process matrices from scenarios involving such agents with quantum clocks, and analyze their properties.
arXiv Detail & Related papers (2021-05-05T20:02:09Z) - Observers of quantum systems cannot agree to disagree [55.41644538483948]
We ask whether agreement between observers can serve as a physical principle that must hold for any theory of the world.
We construct examples of (postquantum) no-signaling boxes where observers can agree to disagree.
arXiv Detail & Related papers (2021-02-17T19:00:04Z) - Self-adjointness in Quantum Mechanics: a pedagogical path [77.34726150561087]
This paper aims to make quantum observables emerge as necessarily self-adjoint, and not merely hermitian operators.
Next to the central core of our line of reasoning, the necessity of a non-trivial declaration of a domain to associate with the formal action of an observable.
arXiv Detail & Related papers (2020-12-28T21:19:33Z) - Agents governed by quantum mechanics can use it intersubjectively and
consistently [0.0]
We propose a simple operational principle called superpositional solipsism to aid rational agents in making situational inferences.
We show that the principle leads to sound inferences in all operationally-relevant instances.
arXiv Detail & Related papers (2020-10-02T19:04:59Z) - Unscrambling the omelette of causation and inference: The framework of
causal-inferential theories [0.0]
We introduce the notion of a causal-inferential theory using a process-theoretic formalism.
Recasting the notions of operational and realist theories in this mold clarifies what a realist account of an experiment offers beyond an operational account.
We argue that if one can identify axioms for a realist causal-inferential theory such that the notions of causation and inference can differ from their conventional (classical) interpretations, then one has the means of defining an intrinsically quantum notion of realism.
arXiv Detail & Related papers (2020-09-07T17:58:22Z) - Experiments on quantum causality [0.0]
Quantum causality extends the conventional notion of fixed causal structure by allowing channels and operations to act in an indefinite causal order.
In this review, we will walk through the basic theory of indefinite causal order and focus on experiments that rely on a physically realisable indefinite causal ordered process.
arXiv Detail & Related papers (2020-09-01T15:25:26Z) - Measuring Quantum Superpositions (Or, "It is only the theory which
decides what can be observed.") [0.0]
We argue that the ad hoc introduction of the projection postulate (or measurement rule) can be understood as a necessary requirement coming from a naive empiricist standpoint.
We discuss the general physical conditions for measuring and observing quantum superpositions.
arXiv Detail & Related papers (2020-07-02T14:30:56Z) - Emergence of classical behavior in the early universe [68.8204255655161]
Three notions are often assumed to be essentially equivalent, representing different facets of the same phenomenon.
We analyze them in general Friedmann-Lemaitre- Robertson-Walker space-times through the lens of geometric structures on the classical phase space.
The analysis shows that: (i) inflation does not play an essential role; classical behavior can emerge much more generally; (ii) the three notions are conceptually distinct; classicality can emerge in one sense but not in another.
arXiv Detail & Related papers (2020-04-22T16:38:25Z) - From a quantum theory to a classical one [117.44028458220427]
We present and discuss a formal approach for describing the quantum to classical crossover.
The method was originally introduced by L. Yaffe in 1982 for tackling large-$N$ quantum field theories.
arXiv Detail & Related papers (2020-04-01T09:16:38Z)
This list is automatically generated from the titles and abstracts of the papers in this site.
This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.