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Equation 10 · Part 2 · How Much of Gravitationally Induced Entanglement Is in the Eye of the Frame

subscript

φent\varphi_{\text{ent}}
subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

The passage around this formula

There is a second honest boundary, and it is about time rather than interpretation. Every real experiment runs for a finite duration in a real environment, and φent\varphi_{\text{ent}} is a property of an idealized, undecohered state. Daine Danielson, Gautam Satishchandran and Robert Wald showed, in a closely related setting, that even a source as gravitationally faint as an ordinary black hole will eventually decohere a spatial superposition through the emission of soft gravitons alone, converting a which-path superposition into which-path information the environment has irrecoverably recorded [ 10 ] . Markus Aspelmeyer’s own essay on this challenge — written for a volume honoring Dieter Zeh,…

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

Open the illustrated subscripts: which member of a family? guide →

Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.