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Equation 6 · Part 1 · A Reference Frame Becomes Classical by Publishing Its Orientation

Symbol θ

θ\theta
θ\theta

What this part means

the detector sits at angle.

Its job in the formula

θ is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Where the article explains it

A Hamiltonian contains JzJ_z ; a detector sits at angle θ\theta ; a photon is called horizontally polarized.

The passage around this formula

A laboratory description often begins with an unmentioned gift: an external frame. A Hamiltonian contains JzJ_z ; a detector sits at angle θ\theta ; a photon is called horizontally polarized. Those symbols presuppose an axis relative to which “z,” “angle,” and “horizontal” have meaning. Quantum-reference-frame research asks what happens when the object providing that axis is finite and quantum.

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the article section

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