← All parts of this equation

Equation 97 · Part 8 · A Horizon Is a Toll Booth, Not a Loophole

subscript

S≤2πkBRE/(ℏc)S\leq 2\pi k_BRE/(\hbar c)
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

A second, independent ceiling bounds not the rate of erasure but the total information a bounded system can hold at all: the Bekenstein bound limits the entropy of a system of effective size R and energy E to S≤\leq 2π\pi kBk_BRE/(ℏ\hbar c) [ 8 ] . For a processor of size R=1\,cm\mathrm{cm} holding E=1\,J\mathrm J of available energy, this gives S≲\lesssim27\,J K−1\mathrm{J\,K^{-1}} , equivalent to roughly 2.9×\times10^{24} bits of maximum distinguishable entropy — a static capacity ceiling, not a rate. Erasing that many bits at 10\,mK\mathrm{mK} would cost at least Qmin⁡Q_{\min}=ST≈\approx0.27\,J\mathrm J , more than a quarter of the entire energy budget assumed available, entirely independent of any horizon.…

Read this part in the article →

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.