The detuned exchange: the hop with a state-dependent energy at the receiver #
Category: 3-Local (CV; the carrier side of BACKLOG #194, the first internally activated write).
The signal exchange of SignalExchange.lean is the hop H = J X. When the receiver's site carries
an energy Δ — in #194 the back-reaction of a pointer coupled to the occupancy of B — the carrier's
Hamiltonian becomes
H(Δ) = J X + Δ n_B = (Δ/2) P + Ω Y, Ω = √(J² + Δ²/4), Y = (J X + (Δ/2) Z)/Ω,
with P the one-excitation projector and Z = n_B − n_A. The two pieces commute, Y² = P, and the
flow is the product of two closed-form exponentials (ExpUnique.lean):
U(t) = 1 + (e^{−iΔt/2ħ} cos(Ωt/ħ) − 1) P − i e^{−iΔt/2ħ} sin(Ωt/ħ) Y.
The receiver's occupancy for message 1 is the detuned Rabi formula (J/Ω)² sin²(Ωt/ħ): the
transfer is no longer complete, and the loss 1 − (J/Ω)² = (Δ/2)²/Ω² is the explicit price of the
back-reaction. The vacuum is fixed, so message 0 produces no occupancy at all.
occA,zOp,rabiFreq,rabiY,detunedH,detunedGen, ★detunedFlow J ħ Δ : FieldStructuredFlow 2 2— the detuned exchange is a field-structured flow on the same edge;detunedGen_zero— atΔ = 0it is the hop of #183;- ★★
detunedFlow_val_eq— the flow in closed form, byexp_add_of_commuteand two uses ofexp_smul_eq_cosh_sinh;detunedFlow_msgPoint_zero— the vacuum is fixed; - ★★
detuned_readout_one— the receiver's occupancy for message1is(J/Ω)² sin²(Ωt/ħ);detuned_readout_zero; ★detuned_readout_one_le,detuned_readout_one_peak,detuned_readout_one_lt_one,one_sub_div_rabiFreq_sq— the detuning loss, attained at the detuned hop time and strictly positive wheneverΔ ≠ 0; - ★
arenaObs_detunedH_arenaFlow— the carrier's energy⟨H(Δ)⟩is conserved along the flow; occHist,occAccum— the receiver's occupancy history and its time integral, for every arena point; ★occAccum_add— the integral obeys the flow's group law; ★hasDerivAt_occAccum— its derivative is the occupancy; ★★occAccum_msgPoint_one— the closed form for message1,(J/Ω)² (Ωt/ħ − sin cos)/(2Ω/ħ);occAccum_msgPoint_zero = 0;continuous_arenaDM,continuous_arenaObs_prod, ★continuous_arenaKick_prod— the arena density, the observables and the unitary kick are continuous, jointly in all arguments, by descent through the open quotient mapmk';continuous_occHist_prod,continuous_occAccum_prod— the history and its integral are continuous jointly in the ray and the detuning, which is what #194's skew product needs.
Honest scope #
- Nothing here is a record. The pointer that produces
Δand reads the occupancy isRecordLayer/ActivatedWrite.lean; this file is its carrier. Δis a real parameter. In #194 it is a function of a conserved torus angle, so the flow at fixed angle is exactly this one; no time dependence appears anywhere.J > 0is assumed where the closed form divides byΩ;ħenters only through the angles.
References: specs/BACKLOG.md #194, #183, #195; CV/SignalExchange.lean (hopX, oneExc,
occB, msgPoint, receiver_readout_one), CV/FieldStructuredFlow.lean, CV/ArenaBridge.lean
(arenaObs_kick_conj, arenaDM_mk), Mathlib/Analysis/Normed/Algebra/ExpUnique.lean,
Mathlib/LinearAlgebra/Projectivization/Topology.lean (isOpenQuotientMap_mk').
Continuity on the arena, jointly in all arguments #
The arena density is continuous, by descent through the quotient map mk': arenaDM is
defined through Projectivization.rep, which is not continuous, but arenaDM (mk v) = dmVec v and
dmVec is continuous on the nonzero vectors.
Arena observables are continuous jointly in the ray and the operator.
An arena observable of a continuous operator family at a continuous family of rays is
continuous. Stated in applied form so that it composes without unfolding arenaObs.
★ The unitary kick is continuous jointly in the unitary and the ray: id × mk' is an open
quotient map, and the lift (U, v) ↦ mk (U v) is continuous.
The kick of a continuous family of unitaries at a continuous family of rays is continuous.
The kick is the unitary action (general index type).
Every unitary kick preserves the Fubini–Study measure at every reference point.
The expectation of a basis projector at a ray is its moment coordinate.
Generic facts about field-structured flows #
The occupancy of A, the imbalance Z, and their algebra #
The occupancy of A.
Equations
Instances For
The imbalance Z = n_B − n_A.
Equations
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Two matrix units whose inner indices differ multiply to zero.
The Rabi frequency and the rescaled traceless part #
The rescaled traceless part Y = (J X + (Δ/2) Z)/Ω, with Y² = P and Y P = Y.
Equations
- CSD.CV.rabiY J Δ = ↑(CSD.CV.rabiFreq J Δ)⁻¹ • (↑J • CSD.CV.hopX + ↑(Δ / 2) • CSD.CV.zOp)
Instances For
The detuned Hamiltonian, its generator and its flow #
The detuned Hamiltonian H(Δ) = J X + Δ n_B.
Equations
- CSD.CV.detunedH J Δ = ↑J • CSD.CV.hopX + ↑Δ • CSD.CV.occB
Instances For
The Schrödinger generator −(i/ħ) H(Δ).
Equations
- CSD.CV.detunedGen J ħ Δ = -(Complex.I * ↑(1 / ħ)) • CSD.CV.detunedH J Δ
Instances For
At zero detuning the generator is the hop's.
★ The detuned exchange as a field-structured flow: the one edge (A, B) carrying −(i/ħ) (J X + Δ n_B).
Equations
Instances For
At zero detuning the flow is the hop's flow.
The flow is continuous jointly in the detuning and the time.
The unitary itself, as a continuous family in the detuning and the time.
The Schrödinger equation of the detuned exchange: U' = G U, with the state-dependent
generator.
The closed form #
★★ The flow in closed form:
U(t) = 1 + (e^{−iΔt/2ħ} cos(Ωt/ħ) − 1) P − i e^{−iΔt/2ħ} sin(Ωt/ħ) Y.
Entries of the closed form #
The transfer amplitude U_{BA}(t) = −i e^{−iΔt/2ħ} · (J/Ω) sin(Ωt/ħ).
The vacuum is fixed by the detuned flow: message 0 never reaches the receiver.
The receiver's readouts under detuning #
The detuned hop time π ħ/(2Ω).
Equations
- CSD.CV.detunedHopTime J ħ Δ = Real.pi * ħ / (2 * CSD.CV.rabiFreq J Δ)
Instances For
The carrier's energy is conserved #
★ Energy conservation on the carrier: ⟨H(Δ)⟩ is constant along the detuned flow.
The energy of the detuned Hamiltonian at a ray: J⟨X⟩ + Δ n_B.
The occupancy history and its time integral #
The receiver's occupancy history along the detuned exchange from p.
Equations
- CSD.CV.occHist J ħ Δ p s = CSD.CV.arenaObs CSD.CV.occB ((CSD.CV.detunedFlow J ħ Δ).arenaFlow s p)
Instances For
The history in Heisenberg form: the occupancy of the evolved ray is the expectation of the evolved occupancy.
The history is continuous jointly in the ray, the detuning and the time, stated in the uncurried form the parametric-integral lemma consumes.
The accumulated receiver occupancy ∫₀ᵗ n_B(p(s)) ds.
Equations
- CSD.CV.occAccum J ħ Δ p t = ∫ (s : ℝ) in 0..t, CSD.CV.occHist J ħ Δ p s
Instances For
The history from the evolved ray is the shifted history.
★ The group law of the accumulated occupancy: A(p, s + t) = A(p, s) + A(U(s)p, t).
★ The pointer's rate: the accumulated occupancy has derivative the occupancy.
The accumulated occupancy is continuous jointly in the ray and the detuning, at every fixed time — the measurability #194's skew product needs.
The two messages #
★★ The accumulated occupancy for message 1 in closed form:
(J/Ω)² (Ωt/ħ − sin(Ωt/ħ) cos(Ωt/ħ)) / (2Ω/ħ).