getting started added and css fixed

Author: sotashimozono

docs/make.jl

@@ -34,7 +34,7 @@ makedocs(;
     modules=[GroverAlgorithm],
     pages=[
         "Home" => "index.md",
-        #"Getting Started" => "getting_started.md",
+        "Getting Started" => "getting_started.md",
         #"Core Concepts" => [
         #    "Quantum Gates and Circuits" => "structures.md",
         #    "Initial States" => "initialstates.md",

docs/src/assets/custom.css

@@ -6,7 +6,7 @@
     margin-bottom: 12px;     /* 下の名前との距離 */
 }
 
-article#documenter-page img[src$=".svg"][alt*="Example block"] {
+article#documenter-page img {
     display: block;
     margin-left: auto;
     margin-right: auto;

docs/src/example/getting_started.md

@@ -0,0 +1,134 @@
+# Getting Started: Your First Quantum Circuit
+
+In this page, you will learn:
+
+- How to construct quantum circuits on GroverAlgorithm.jl
+- How quantum circuits on GroverAlgorithm.jl works in ITensors and Quantikz.
+
+## Install
+
+In order to use visualize functions, `LaTeX` and `Quantikz` may be needed.
+
+```julia
+using Pkg
+Pkg.add(url="https://github.com/sotashimozono/GroverAlgorithm.jl")
+Pkg.add("ITensors")
+Pkg.add("ITensorMPS")
+```
+
+## Basics
+
+In GroverAlgorithm.jl, use quantum circuits as follows:
+
+1. Construct circuit - define circuit by adding desired gates.
+2. Simulation on ITensors.jl - calculate quantum states.
+3. Visualize circuits on Quantikz - generate circuits figure on LaTeX
+
+## Example: Hadamard gate
+
+Let's consider from easiest one.
+
+### step1: Construct gate
+
+```@example getting_started
+using GroverAlgorithm
+using ITensors, ITensorMPS
+
+# 1 site qubit
+circuit = QuantumCircuit(1, AbstractQuantumGate[])
+
+# add Hadamard gate
+add_gate!(circuit, SingleQubitGate(1, :H))
+
+println("circuit information:")
+println("  number of qubits: ", circuit.nqubits)
+println("  number of gates: ", length(circuit.gates))
+```
+
+### step2: Simulation on ITensors.jl
+
+```@example getting_started
+using ITensors, ITensorMPS
+
+# site index
+sites = siteinds("Qubit", 1)
+
+# execute circuit
+psi = execute_circuit(circuit, sites)
+
+# MPS info
+println("\nMPS (Matrix Product State):")
+println(psi)
+```
+
+structure of MPS：
+
+```@example getting_started
+println("amplitude of quantum states:")
+amp_0 = inner(psi, MPS(sites, ["0"]))
+amp_1 = inner(psi, MPS(sites, ["1"]))
+
+println("  ⟨0|ψ⟩ = ", amp_0, " (probability: ", abs2(amp_0), ")")
+println("  ⟨1|ψ⟩ = ", amp_1, " (probability: ", abs2(amp_1), ")")
+```
+
+this means the state $|\psi\rangle$ is superposition of $|0\rangle, |1\rangle$:  
+$$\begin{aligned}
+|\psi\rangle = \frac{|0\rangle+|1\rangle}{\sqrt2}
+\end{aligned}$$
+
+### step3: Visualization on Quantikz
+
+```@example getting_started
+# generate LaTeX string of quantikz
+latex_code = to_quantikz(circuit)
+println("Quantikz LaTeX code:")
+println(latex_code)
+```
+
+This LaTeX code generates following：
+
+```@example getting_started
+to_tikz_picture(circuit)
+```
+
+## Example2: Bell state（Entanglement）
+
+Next, we construct 2-site qubit.
+
+### step1: construct circuits
+
+```@example getting_started
+circuit = QuantumCircuit(2, AbstractQuantumGate[])
+
+add_gate!(circuit, SingleQubitGate(1, :H))
+add_gate!(circuit, ControlledGate(1, 2, :CNOT))
+
+println("Bell state circuit:")
+println("  gate1: H on qubit 1")
+println("  gate2: CNOT (control: 1, target: 2)")
+```
+
+### step2: Simulation on ITensors
+
+```@example getting_started
+sites = siteinds("Qubit", 2)
+psi = execute_circuit(circuit, sites)
+
+println("amplitude of Bell state:")
+for s in ["00", "01", "10", "11"]
+    basis = MPS(sites, [string(c) for c in s])
+    amp = inner(basis, psi)
+    prob = abs2(amp)
+    println("  ⟨$s|ψ⟩ = ", round(amp, digits=4), " (probability: ", round(prob, digits=4), ")")
+end
+```
+
+### step3: Visualize circuit on Quantikz
+
+```@example getting_started
+latex_code = to_quantikz(circuit)
+println(latex_code)
+
+to_tikz_picture(circuit)
+```