Piecemaker

.gitignore

@@ -2,4 +2,5 @@ Manifest.toml
 build
 .gitignore
 ROADMAP.md
-coverage
+coverage
+.DS_Store

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "julia.environmentPath": "/Users/localadmin/Documents/github/QuantumSavory.jl/examples/piecemakerswitch"
+}

Project.toml

@@ -1,7 +1,7 @@
 name = "QuantumSavory"
 uuid = "2de2e421-972c-4cb5-a0c3-999c85908079"
 authors = ["Stefan Krastanov <[email protected]>"]
-version = "0.6"
+version = "0.6.0"
 
 [deps]
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"

examples/piecemakerswitch/Project.toml

@@ -0,0 +1,11 @@
+[deps]
+CSV = "336ed68f-0bac-5ca0-87d4-7b16caf5d00b"
+ConcurrentSim = "6ed1e86c-fcaf-46a9-97e0-2b26a2cdb499"
+DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
+Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
+Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
+NetworkLayout = "46757867-2c16-5918-afeb-47bfcb05e46a"
+QuantumSavory = "2de2e421-972c-4cb5-a0c3-999c85908079"
+ResumableFunctions = "c5292f4c-5179-55e1-98c5-05642aab7184"
+Revise = "295af30f-e4ad-537b-8983-00126c2a3abe"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

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. 
+
+### 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 +1,70 @@
+using QuantumSavory
+using QuantumSavory.ProtocolZoo
+using Graphs
+using ConcurrentSim
+using ResumableFunctions
+using Distributions
+using DataFrames
+using CSV
+using Profile
+using NetworkLayout
+
+@resumable function entangle_and_fuse(sim, net, client, link_success_prob)
+
+    # Set up the entanglement trackers at each client
+    tracker = EntanglementTracker(sim, net, client) 
+    @process tracker()
+
+    # Set up the entangler and fuser protocols at each client
+    entangler = EntanglerProt(
+        sim=sim, net=net, nodeA=1, slotA=client-1, nodeB=client,
+        success_prob=link_success_prob, rounds=1, attempts=-1,
+        start_timer_after_first_attempt=true, # TODO: for some reason attempt_timeout=1 is not working, hardcoded in constructor for now
+        )
+    @yield @process entangler()
+
+    fuser = FusionProt(
+            sim=sim, net=net, node=1,
+            nodeC=client,
+            rounds=1
+        )
+    @yield @process fuser()
+end
+
+
+@resumable function run_protocols(sim, net, nclients, link_success_prob)
+    # Run entangler and fusion for each client and wait for all to finish
+    procs_succeeded = []
+    for k in 2:nclients+1    
+        proc_succeeded = @process entangle_and_fuse(sim, net, k, link_success_prob)
+        push!(procs_succeeded, proc_succeeded)
+    end
+    @yield reduce(&, procs_succeeded)
+end
+
+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)
+
+    # Run entangler and fusion for each client and wait for all to finish
+    @process run_protocols(sim, net, nclients, link_success_prob)
+
+    # Set up the consumer to measure final entangled state
+    consumer = FusionConsumer(net, net[1][m]; period=1)
+    @process consumer()
+
+    return sim, consumer
+end
+

examples/piecemakerswitch/simple_run.jl

@@ -0,0 +1,60 @@
+include("setup.jl")
+using DataFrames
+using CSV
+
+
+# Set up the simulation parameters
+name = "qs_piecemeal"
+nruns = 1000
+mem_depolar_prob = 0.1
+link_success_prob = 0.5
+
+results_per_client = DataFrame[]
+for nclients in 2:9
+    # Prepare simulation data storage
+    distribution_times = Float64[]
+    fidelities = Float64[]
+    elapsed_times = Float64[]
+
+    # Run the simulation nruns times
+    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
+
+    # Fill the 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/piecemaker-eventdriven.csv", results_total)
+# CSV.write("examples/piecemakerswitch/output/piecemaker-eventdriven_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