High School How does a spinor affect a wave function?

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Spinors significantly influence wave function solutions by introducing additional components that represent the spin of particles, as seen in the Dirac equation. A particle's wave function combines spatial components with spinors, allowing for multiple states, such as two electrons sharing the same spatial wave function. This interaction has profound implications in fields like chemistry, particularly in understanding atomic structures like helium. The algebraic properties of spinors, which can have multiple complex components, characterize their role in wave functions. Ultimately, the presence of spinors enriches the mathematical framework of quantum mechanics, affecting how wave functions are represented and understood.
justpeeking
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How do spinors affect wave function solutions? Like how is the output different
 
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justpeeking said:
How do spinors affect wave function solutions? Like how is the output different
The wave function of a particle with spin is the composition of a spatial component and a spinor. See the Dirac equation, for example:

https://en.wikipedia.org/wiki/Dirac_equation
 
justpeeking said:
How do spinors affect wave function solutions? Like how is the output different
Due to spin, you can have a state with two electrons with the same spatial wave function. It has dramatic consequences for chemistry, see e.g. https://en.wikipedia.org/wiki/Helium_atom.
 
PeroK said:
The wave function of a particle with spin is the composition of a spatial component and a spinor. See the Dirac equation, for example:

https://en.wikipedia.org/wiki/Dirac_equation

Respecting your expertise and appreciating Demystifier's enlightening answer, nevertheless might a slightly more illluminating answer* to the question be:

A spinor wave function has multiple spatial components (four for a single-electron solution of the Dirac equation).

It is the algebraic properties of this multicomponent object that makes it a spinor.

In the case of Pauli's early phenomenological theory of spin, he developed spinors that had 2-complex components (just two complex numbers). These can be combined with spatial wave functions, as your own answer states, in a manner that is very clearly illustrated in Richard Fitzpatrick's article https://farside.ph.utexas.edu/teaching/qm/lectures/node51.html

So rather than ask "How ... spinors affect wave function solutions" it might be better to ask "what characterises a wave function solution as a spinor" (i.e. being components of a spinors doesn't change (affect) the spatial wave functions themselves, but rather associates them in such a way that the whole mathematical object is - has the properties of - a spinor.)

* OK - pedantic if you prefer
 
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Time reversal invariant Hamiltonians must satisfy ##[H,\Theta]=0## where ##\Theta## is time reversal operator. However, in some texts (for example see Many-body Quantum Theory in Condensed Matter Physics an introduction, HENRIK BRUUS and KARSTEN FLENSBERG, Corrected version: 14 January 2016, section 7.1.4) the time reversal invariant condition is introduced as ##H=H^*##. How these two conditions are identical?

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