Exploring the limits of no backwards in time signalling

We present an operational and model-independent framework to investigate the concept of no-backwards-in-time signalling. We define no-backwards-in-time signalling conditions, closely related to the spatial no-signalling conditions. These allow for theoretical possibilities in which the future affects the past, nevertheless without signalling backwards in time. This is analogous to non-local but no-signalling spatial correlations. Furthermore, our results shed new light on situations with indefinite causal structure and their connection to quantum theory.

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Causation does not explain contextuality

Quantum ◽

10.22331/q-2018-05-18-63 ◽

2018 ◽

Vol 2 ◽

pp. 63 ◽

Cited By ~ 5

Author(s):

Sally Shrapnel ◽

Fabio Costa

Keyword(s):

Quantum Mechanics ◽

Causal Structure ◽

Quantum Correlations ◽

Global Constraints ◽

Local Constraints ◽

The Past ◽

Interpretations Of Quantum Mechanics ◽

The World ◽

Non Local ◽

Initial States

Realist interpretations of quantum mechanics presuppose the existence of elements of reality that are independent of the actions used to reveal them. Such a view is challenged by several no-go theorems that show quantum correlations cannot be explained by non-contextual ontological models, where physical properties are assumed to exist prior to and independently of the act of measurement. However, all such contextuality proofs assume a traditional notion of causal structure, where causal influence flows from past to future according to ordinary dynamical laws. This leaves open the question of whether the apparent contextuality of quantum mechanics is simply the signature of some exotic causal structure, where the future might affect the past or distant systems might get correlated due to non-local constraints. Here we show that quantum predictions require a deeper form of contextuality: even allowing for arbitrary causal structure, no model can explain quantum correlations from non-contextual ontological properties of the world, be they initial states, dynamical laws, or global constraints.

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The arrow of time in operational formulations of quantum theory

Quantum ◽

10.22331/q-2021-08-09-520 ◽

2021 ◽

Vol 5 ◽

pp. 520

Author(s):

Andrea Di Biagio ◽

Pietro Donà ◽

Carlo Rovelli

Keyword(s):

Quantum Theory ◽

Time Orientation ◽

Implicit Assumption ◽

Arrow Of Time ◽

Mathematical Objects ◽

The Past ◽

The Future ◽

The Asymmetry ◽

The Difference

The operational formulations of quantum theory are drastically time oriented. However, to the best of our knowledge, microscopic physics is time-symmetric. We address this tension by showing that the asymmetry of the operational formulations does not reflect a fundamental time-orientation of physics. Instead, it stems from built-in assumptions about the users of the theory. In particular, these formalisms are designed for predicting the future based on information about the past, and the main mathematical objects contain implicit assumption about the past, but not about the future. The main asymmetry in quantum theory is the difference between knowns and unknowns.

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The Arguments of Time

10.5871/bacad/9780197263464.001.0001 ◽

2006 ◽

Cited By ~ 3

Keyword(s):

General Relativity ◽

Quantum Theory ◽

Quantum Gravity ◽

The Past ◽

The Future

These nine chapters, commissioned on the initiative of the Philosophy section of the British Academy, address fundamental questions about time in philosophy, physics, linguistics, and psychology. Are there facts about the future? Could we affect the past? Physics, general relativity and quantum theory give contradictory treatments of time. So in the search for a theory of quantum gravity, which should give way: general relativity or quantum theory? In linguistics and psychology, how does our language represent time, and how do our minds keep track of it?

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Futures literacy in the loop

European Journal of Futures Research ◽

10.1186/s40309-021-00187-y ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Jan Erik KARLSEN

Keyword(s):

Feedback Control ◽

Causal Structure ◽

Initial Period ◽

Causal Effects ◽

The Core ◽

The Past ◽

Body Of Knowledge ◽

The Future ◽

Functional Explanations ◽

Images Of The Future

AbstractThis article proposes a functional historicist explanation to explicate the core ideas and underlying logic embedded in the futures literacy concept.Futures literacy assumes a capacity to reflect on the past, sense and make sense of the present and use this reflective body of knowledge when anticipating the future.Arguably, futures literacy must be learned, sustained, and regained; it requires a continuous, anticipative, and recursive loop. Recursivity, where an effect in an initial period acts as a cause in the next period, retroacts between the future and present, regaining anticipation. Anticipation has causal effects in the way it structures our images of the future and the avenue we follow when striving to achieve this image. Such a causal structure implies both feedforward and feedback control and is contained in the logic of functional explanations used in sociology.

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