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∣ddτln⁡ ⁣[⟨H(τ)⟩−E0(τ)]∣≪2[⟨H(τ)⟩−E0(τ)]πℏ\left|\frac{d}{d\tau}\ln\!\left[\langle H(\tau)\rangle - E_0(\tau)\right]\right| \ll \frac{2\left[\langle H(\tau)\rangle-E_0(\tau)\right]}{\pi\hbar}

Why this formula appears here

The dossier for this paper flags something the two equations above do not, by themselves, settle: the periodic-evolution bound above was derived for a Hamiltonian with a genuinely time-independent spectrum. A real computation drives H(τ\tau) through a sequence of different instantaneous Hamiltonians, one per gate, and nothing guarantees in advance that a chain of instantaneously applied bounds sums to a valid bound on the whole chain. The condition that licenses treating N⊥N_\perp[Γ\Gamma] as a legitimate partition into instantaneously static Levitin-Toffoli steps is a quasi-static one: over one local orthogonalization time τML(τ)\tau_{\rm ML}(\tau) = π\piℏ\hbar/[2(⟨\langle H(τ\tau)⟩\rangle-E0(τ)E_0(\tau))] ,…

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dd

Symbol d

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

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π\pi

Symbol pi

pi occurs below the fraction bar. The quantity above the bar is divided by this expression; zero is excluded as a denominator.

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2[⟨H(τ)⟩−E0(τ)]2\left[\langle H(\tau)\rangle-E_0(\tau)\right]

Numerator: 2[langle H(τ)rangle-E_0(τ)]

The complete quantity above the fraction bar.

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How to interpret it

With a fixed numerator, increasing a nonzero denominator reduces the fraction.

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Published contexts (1)

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∣ddτln⁡ ⁣[⟨H(τ)⟩−E0(τ)]∣≪2[⟨H(τ)⟩−E0(τ)]πℏ.\left|\frac{d}{d\tau}\ln\!\left[\langle H(\tau)\rangle - E_0(\tau)\right]\right| \ll \frac{2\left[\langle H(\tau)\rangle-E_0(\tau)\right]}{\pi\hbar}.

Equation 37 · Evolutionary Physics

A Horizon Is a Toll Booth, Not a Loophole

This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.

The dossier for this paper flags something the two equations above do not, by themselves, settle: the periodic-evolution bound above was derived for a Hamiltonian with a genuinely time-independent spectrum. A real computation drives H(τ\tau) through a sequence of different instantaneous Hamiltonians, one per gate, and nothing guarantees in advance that a chain of instantaneously applied bounds sums to a valid bound on the whole chain. The condition that licenses treating N⊥N_\perp[Γ\Gamma] as a legitimate partition into instantaneously static Levitin-Toffoli steps is a quasi-static one: over one local orthogonalization time τML(τ)\tau_{\rm ML}(\tau) = π\piℏ\hbar/[2(⟨\langle H(τ\tau)⟩\rangle-E0(τ)E_0(\tau))] ,…

Meanings in this article

  • τ\tau: a time, the integral has action units.
  • E0E_0: the ground-state energy of H [ 2 , 1 ].
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