Nuclear decay emission: deterministic modeling?

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Discussion Overview

The discussion centers on the possibility of modeling nuclear decay emissions, specifically alpha and gamma emissions, in a deterministic manner. Participants explore whether it is feasible to predict the origin and direction of emitted particles through theoretical models, considering both quantum mechanics and specific experimental contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that it may be theoretically possible to model nucleon interactions deterministically to determine the origin and direction of emitted particles during nuclear decay.
  • Others argue that nuclear decay is fundamentally a quantum mechanical process, characterized by statistical behavior, where individual decay events cannot be predicted, only the behavior of large collections of nuclei.
  • A participant mentions that while the direction of emitted particles is influenced by conservation laws, it remains non-deterministic due to the variable momentum of the emitted particles and the potential for angular momentum considerations to affect probabilities.
  • Another participant introduces the Bohmian interpretation of quantum mechanics, suggesting that it allows for a deterministic modeling of all quantum processes, including nuclear decay.
  • One participant highlights that in specific cases, such as β-decays in aligned magnetic fields, the direction of emitted particles can be influenced by external conditions, providing a reference direction for measurements.
  • A question is raised about the indeterministic nature of photon emissions during d-d electronic transitions in conventional quantum mechanics, suggesting a broader inquiry into the determinism of various quantum processes.

Areas of Agreement / Disagreement

Participants express differing views on the determinism of nuclear decay emissions, with some supporting the idea of deterministic modeling while others emphasize the inherent statistical nature of quantum processes. The discussion remains unresolved regarding the feasibility of deterministic models in this context.

Contextual Notes

The discussion reflects limitations in the ability to predict specific outcomes in quantum systems, such as the exact location and direction of emissions, due to the complexities of strongly interacting systems and the nature of wavefunctions.

Hypatio
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Is it possible, in theory, that a radioisotope undergoing nuclear decay (eg. alpha particle emission) can be modeled so as to determine the origin and/or direction of the emitted particle? For instance, perhaps one could model nucleon interactions deterministically and observe that when the interactions occur in a certain way it causes an emission.

If so, will this also work for gamma emission? Could you not only model where in the system the emission occurs, but its direction?
 
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Decay is a quantum mechanical process. Theory, in principle (since it is hard to solve strongly-interacting systems), can determine a partial decay rate for a nucleus for each decay mode. Beyond that, the decay is statistical, in the sense that there is no determined time for a single nucleus, but if we study a large collection of them, we can talk about the fraction of nuclei that we expect to have decayed in some period of time.

We also can't really say where in the nucleus the decay started, since the nucleons are smeared according to the wavefunction. Again, this is a strongly interacting system, so we don't have exact wavefunctions, but we do know that the nucleons are not localized at points and there is even a large virtual particle contribution to the nuclear state.

The direction of the emitted particle is a kinematical distribution dictated by conservation of energy and momentum. Since the nucleus is always allowed to recoil a bit, the momentum of the emitted particle is variable and hence so is its direction. Angular momentum considerations might make some directions more probable than others, but the precise direction is not deterministic.
 
Hypatio said:
Is it possible, in theory, that a radioisotope undergoing nuclear decay (eg. alpha particle emission) can be modeled so as to determine the origin and/or direction of the emitted particle? For instance, perhaps one could model nucleon interactions deterministically and observe that when the interactions occur in a certain way it causes an emission.

If so, will this also work for gamma emission? Could you not only model where in the system the emission occurs, but its direction?
Yes, it's possible. For example, Bohmian interpretation of quantum mechanics models ALL quantum processes deterministically.
 
The obvious case where the direction of the emitted particle may vary is in β-decays of nuclei whose spins have been aligned within a magnetic field. Here, the direction of the field defines a reference direction in space against which other measurables can be plotted.

A classic experiment was done using 60Co in a magnetic field to measure the anisotropy of the emitted βs, and hence confirm that the weak force violates parity conservation.
 
Last edited:
Are the directions of d-d electronic transitions (photon emissions) also indeterministic in conventional quantum mechanics?
 

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