Predefined Models of Quantum States

struct BarrettKokBellPair <: QuantumSavory.StatesZoo.AbstractTwoQubitState

Fields:

• ηᴬ: Individual channel transmissivity from source A to entanglement swapping station, ∈[0,1]

• ηᴮ: Individual channel transmissivity from source B to entanglement swapping station, ∈[0,1]

• Pᵈ: Total excess noise (photons per qubit slot) in photon detectors, ≥0, usually ≪1

• ηᵈ: Detection efficiency of photon detectors, ∈[0,1]

• 𝒱: Mode matching parameter for individual interacting photonic pulses with |V| evaluates mode overlap and arg(V) evaluates the carrier phase mismatch, |V|∈[0,1]

• m: A single parity bit determined by the click pattern (m = 0 for [0, 1, 1, 0] or [1, 0, 0, 1]; m = 1 for [1, 1, 0, 0] or [0, 0, 1, 1])

• metadata

A symbolic representation of the noisy Bell pair state obtained in a Barrett-Kok style protocol (a sequence of two successful entanglement swaps), referred to as the "dual rail photonic qubit swap" in (Prajit Dhara and Guha, 2023) (see eq. C7).

See also BarrettKokBellPairW for the weighted density matrix.

BarrettKokBellPair(ηᴬ,ηᴮ)

Asymmetric noiseless perfectly mode-matched case ηᴬ≠ηᴮ, Pᵈ=0, ηᵈ=1, 𝒱=1, m=0

BarrettKokBellPair(η)

Symmetric noiseless perfectly mode-matched case ηᴬ=ηᴮ=η, Pᵈ=0, ηᵈ=1, 𝒱=1, m=0

The weighted version of BarrettKokBellPair, i.e. its trace is the probability of successfully heralding a Barrett-Kok Bell pair.

The normalized version of MultiplexedCascadedBellPairW.

struct MultiplexedCascadedBellPairW <: QuantumSavory.StatesZoo.AbstractTwoQubitState

Fields:

• ηᴬᵐ: Outcoupling transmissivity of photon from Alice’s spin memory, ∈[0,1]

• ηᴮᵐ: Outcoupling transmissivity of photon from on Bob’s spin memory, ∈[0,1]

• ηᴬˢ: Outcoupling transmissivity on Alice’s side of HMCS (or signal), ∈[0,1]

• ηᴮˢ: Outcoupling transmissivity on Bob’s side of HMCS (or idler), ∈[0,1]

• ηᶜ¹: Coupling from SPDC source 1 to linear optical BSM (implicitly must account for detection efficiency)

• ηᶜ²: Coupling from SPDC source 2 to linear optical BSM (implicitly must account for detection efficiency)

• N: Mean photon number per mode of the state. This is a tradeoff parameter for fidelity vs rate. It has to be >0 (but the model becomes imprecise at N>0.2 due to the 2-photon cutoff of the Fock space used in derivation)

• Pᵈ: Excess noise (photons per qubit slot) in photon detectors for swap of HMCS, ≥0, usually ≪1

• Pᴬᵈ: Excess noise (photons per qubit slot) in photon detectors for swap on Alice's side, ≥0, usually ≪1

• Pᴮᵈ: Excess noise (photons per qubit slot) in photon detectors for swap on Bob's side, ≥0, usually ≪1

• vis: Swap visibility product, ∈[0,1]

• gᴬ: Spin qubit initialization parameter on Alice's side, ∈[0,1], usually =½

• gᴮ: Spin qubit initialization parameter on Bob's side, ∈[0,1], usually =½

• metadata

Heralded multiplexed cascaded source (a.k.a. single mode model for zero added loss multiplexed (ZALM) source), after a swap with spin-½ memories.

The state is not normalized and its trace corresponds to the probability of successful heralding.

Based on the cascaded source from (and Guha, 2022) and (and Englund, 2023) after being stored in spin memories as discussed in (Prajit Dhara and Guha, 2023).

Symmetric noiseless perfectly mode-matched well-initialized case ηᵐ=ηᴬᵐ=ηᴮᵐ, ηˢ=ηᴬˢ=ηᴮˢ, ηᶜ=ηᶜ¹=ηᶜ², Pᵈ=Pᴬᵈ=Pᴮᵈ, vis=1, gᴬ=gᴮ=½

An interactive explorer for two-qubit states. It returns a new figure.

Requires a Makie plotting backend to be imported.

An interactive explorer for two-qubit states. It modifies the given figure.

Requires a Makie plotting backend to be imported.

Return the "interesting" parameters that a state from the StatesZoo has. A constructor that uses only these parameters needs to exist.

Used by stateexplorer to generate the most valuable plots of figures of merit.

Return the valid ranges and the "good" value for all parameters listed in stateparameters.