Piecemaker

Project.toml

@@ -1,11 +1,13 @@
 name = "QuantumSavory"
 uuid = "2de2e421-972c-4cb5-a0c3-999c85908079"
 authors = ["Stefan Krastanov <[email protected]>"]
-version = "0.6"
+version = "0.6.0"
 
 [deps]
+CSV = "336ed68f-0bac-5ca0-87d4-7b16caf5d00b"
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 ConcurrentSim = "6ed1e86c-fcaf-46a9-97e0-2b26a2cdb499"
+DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
 Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
@@ -22,7 +24,9 @@ QuantumSymbolics = "efa7fd63-0460-4890-beb7-be1bbdfbaeae"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 ResumableFunctions = "c5292f4c-5179-55e1-98c5-05642aab7184"
+Revise = "295af30f-e4ad-537b-8983-00126c2a3abe"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+StatsPlots = "f3b207a7-027a-5e70-b257-86293d7955fd"
 SumTypes = "8e1ec7a9-0e02-4297-b0fe-6433085c89f2"
 
 [weakdeps]

examples/piecemakerswitch/README.md

@@ -0,0 +1,52 @@
+# System Overview
+A central switch node connects to **n** clients. The switch possesses **m = n + 1** qubit slots, while each client has a single qubit slot.
+
+# Entanglement Initiation
+At each clock tick, the switch initiates entanglement attempts with each of the **n** clients, resulting in **n** entanglement processes per cycle. Successful entanglement links are then merged into a GHZ (Greenberger–Horne–Zeilinger) state using an additional "piecemaker" qubit located in the \((n + 1)\)th slot of the switch node. This fusion process is assumed to occur instantaneously. Once all clients went through the fusion operation, the piecemaker qubit is measured out. This completes the fusing process and all nodes are sharing an n-GHZ state.
+
+# Fusion Operation
+The fusion operation consists of applying a **CNOT** gate followed by a measurement in the computational basis. This procedure allows the merging of two GHZ states into a single GHZ state, modulo any required Pauli corrections. We iterate over all existing entangled states with the switch node: in each iteration, the piecemaker qubit (initialized in the state \(|+\rangle\)) is fused with one of the existing entangled states. 
+
+# Noise 
+The memories residing the nodes' `Register`s suffer from depolarizing noise. The latter is modelled via Kraus operators applied to the current state's density matrix.
+
+### Protocol flow
+
+```mermaid
+sequenceDiagram
+    participant Client1
+    participant ClientN
+
+    participant SwitchNode
+    participant Log
+
+    Note over Client1,SwitchNode: Round 1 (1 unit time)
+    par Entanglement Generation
+        Client1->>+SwitchNode: Try to generate entanglement
+        ClientN->>+SwitchNode: Try to generate entanglement
+    end
+
+    SwitchNode->>SwitchNode: Run fusions with successful clients
+
+    par Send Measurement Outcomes
+        SwitchNode-->>-Client1: Send measurement outcomes
+        SwitchNode-->>-ClientN: Send measurement outcomes
+    end
+
+    par Apply Corrections (No time cost)
+        Client1->>Client1: Apply correction gates
+        ClientN->>ClientN: Apply correction gates
+    end
+
+    loop Check Fusion Status (No time cost)
+        SwitchNode->>SwitchNode: Check if all clients are fused
+        alt All clients fused
+            SwitchNode->>SwitchNode: Measure piecemaker
+            SwitchNode->>SwitchNode: Compute fidelity to GHZ state
+            SwitchNode->>Log: Log fidelity and time
+            SwitchNode->>SwitchNode: Trigger STOP
+        else
+            SwitchNode->>SwitchNode: Keep checking
+        end
+    end
+```

examples/piecemakerswitch/setup.jl

@@ -0,0 +1,45 @@
+using QuantumSavory
+using QuantumSavory.ProtocolZoo
+using Graphs
+using ConcurrentSim
+using ResumableFunctions
+using Distributions
+using DataFrames
+using CSV
+using StatsPlots
+
+
+function prepare_simulation(nclients=2, mem_depolar_prob = 0.1, link_success_prob = 0.5)
+
+    m = nclients+1 # memory slots in switch is equal to the number of clients + 1 slot for piecemaker qubit
+    r_depol =  - log(1 - mem_depolar_prob) # depolarization rate
+
+    # The graph of network connectivity. Index 1 corresponds to the switch.
+    graph = star_graph(nclients+1)
+
+    switch_register = Register(m, Depolarization(1/r_depol)) # the first slot is reserved for the 'piecemaker' qubit used as fusion qubit 
+    client_registers = [Register(1, Depolarization(1/r_depol)) for _ in 1:nclients] #Depolarization(1/r_depol)
+    net = RegisterNet(graph, [switch_register, client_registers...])
+    sim = get_time_tracker(net)
+
+    # Set up the initial |+> state of the piecemaker qubit
+    initialize!(net[1][m], X1)
+
+    event_ghz_state = Event(sim)
+
+    # Set up the entanglement trackers at each client
+    trackers = [EntanglementTracker(sim, net, k) for k in 2:nclients+1]
+    for tracker in trackers
+        @process tracker()
+    end
+
+    # Finally, set up the switch without assignments
+    switch_protocol = FusionSwitchDiscreteProt(net, 1, 2:nclients+1, fill(link_success_prob, nclients); ticktock=1)
+    @process switch_protocol()
+
+    # Set up an entanglement consumer between each unordered pair of clients
+    consumer = FusionConsumer(net, net[1][m], event_ghz_state; period=1)
+    @process consumer()
+
+    return sim, consumer
+end

examples/piecemakerswitch/simple_run.jl

@@ -0,0 +1,57 @@
+include("setup.jl")
+using DataFrames
+using CSV
+
+name = "qs_piecemeal"
+nruns = 1000
+mem_depolar_prob = 0.1
+link_success_prob = 0.5
+
+results_per_client = DataFrame[]
+for nclients in 2:3
+    # Prepare simulation components
+    distribution_times = Float64[]
+    fidelities = Float64[]
+    elapsed_times = Float64[]
+
+    for i in 1:nruns
+        sim, consumer = prepare_simulation(nclients, mem_depolar_prob, link_success_prob)
+        elapsed_time = @elapsed run(sim)
+
+        # Extract data from consumer.log
+        distribution_time, fidelity = consumer.log[1]
+        append!(distribution_times, distribution_time)
+        append!(fidelities, fidelity)
+        append!(elapsed_times, elapsed_time)
+        @info "Run $i completed"
+    end
+
+    # Initialize results DataFrame
+    results = DataFrame(
+        distribution_times = distribution_times,
+        fidelities = fidelities,
+        elapsed_times = elapsed_times
+    )
+    results.num_remote_nodes .= nclients
+    results.link_success_prob .= link_success_prob
+    results.mem_depolar_prob .= mem_depolar_prob
+    results.type .= name
+
+    push!(results_per_client, results)
+    @info "Clients $nclients completed"
+end
+results_total = vcat(results_per_client...)
+
+# Group and summarize the data
+grouped_df = groupby(results_total, [:num_remote_nodes, :distribution_times])
+summary_df = combine(
+    grouped_df,
+    :fidelities => mean => :mean_fidelities,
+    :fidelities => std => :std_fidelities
+)
+
+@info summary_df
+
+# Write results to CSV
+# CSV.write("examples/piecemakerswitch/output/piecemaker2-9.csv", results_total)
+# CSV.write("examples/piecemakerswitch/output/piecemaker2-9_summary.csv", summary_df)

src/CircuitZoo/CircuitZoo.jl

@@ -3,7 +3,7 @@ module CircuitZoo
 using QuantumSavory
 using DocStringExtensions
 
-export EntanglementSwap, LocalEntanglementSwap,
+export EntanglementFusion, EntanglementSwap, LocalEntanglementSwap,
     Purify2to1, Purify2to1Node, Purify3to1, Purify3to1Node,
     PurifyStringent, PurifyStringentNode, PurifyExpedient, PurifyExpedientNode,
     SDDecode, SDEncode
@@ -46,6 +46,16 @@ end
 
 inputqubits(::LocalEntanglementSwap) = 2
 
+struct EntanglementFusion <: AbstractCircuit
+end
+
+function (::EntanglementFusion)(localq,  piecemaker)
+    apply!((piecemaker, localq), CNOT)
+    zmeas = project_traceout!(localq, σᶻ)
+    zmeas
+end
+
+inputqubits(::EntanglementFusion) = 2
 
 """
 $TYPEDEF