Distributed Quantum Computing: Remote Gate Teleportation

Remote Gate

Input Qubit at Node A

Polar angle θ 0°

Azimuth φ 0°

Node A holds |ψ⟩. Node B is idle.

Network State

|ψ⟩ = 1.00|0⟩ at Node A

Bell outcome

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Gate fidelity

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Runs completed

Classical bits sent

How it works

Two quantum processors (QPU-A, QPU-B) share one entangled pair, prepared as (I⊗U)|Φ+⟩ so Bob's half already carries the gate U dressed onto a Bell pair:

|Φ+⟩ = (|00⟩ + |11⟩)/√2
resource = (I ⊗ U)|Φ+⟩

Alice performs a joint Bell-basis measurement on her data qubit |ψ⟩ and her half of the pair. Expanding the 3-qubit state in that Bell basis shows Bob's qubit collapses to one of four outcomes with equal 25% probability:

|ψ⟩⊗resource = ½ Σ_k |Bell_k⟩_AB ⊗ (U·P_k)|ψ⟩

Alice sends her 2-bit outcome k over an ordinary classical channel. Bob applies the matching correction D_k = U·P_k^-1·U^-1, leaving his qubit in exactly U|ψ⟩ — the gate has acted on a qubit it never touched, using one shared ebit and two classical bits (Gottesman–Chuang gate teleportation, 1999).

H, X, Z, S — pick the gate to apply remotely at Node B.
θ, φ sliders — set the unknown input state |ψ⟩ living at Node A.
Run Protocol — samples a real Bell-measurement outcome, animates the classical bits crossing the channel, then applies Bob's correction.

Because Bob's qubit is only usable once the classical bits arrive (bounded by light speed), the protocol cannot signal faster than light — the fidelity always converges to ~100%, but never before the classical packet lands. This exact primitive is what lets separate quantum chips be wired into one larger distributed quantum computer.

QPU-A (Alice)QPU-B (Bob)

Data / output qubit Shared entangled channel Classical bits (2)

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