1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
use crate::common::{print_section, BenchmarkResult};
use libpsi_core::{
complex, DensityMatrix, NoiseChannel, QuantumCircuit, Runtime, Vector,
};
use std::time::Instant;
pub fn run_all(results: &mut Vec<BenchmarkResult>) {
println!("═══════════════════════════════════════════════════════════════");
println!(" NOISE CHANNEL TESTS");
println!("═══════════════════════════════════════════════════════════════\n");
test_density_matrix_basics(results);
test_noise_channels(results);
test_noisy_circuit(results);
}
pub fn test_density_matrix_basics(results: &mut Vec<BenchmarkResult>) {
print_section("Density Matrix Basics");
let dm = DensityMatrix::new(2);
println!("Initial |00⟩ state:");
println!("{}", dm);
let mut circuit = QuantumCircuit::new(2);
circuit.h(0).cnot(0, 1);
circuit.compute_with(Runtime::BasicRT);
let state = circuit.state();
let state_vec: Vec<_> = (0..state.size())
.map(|i| state.get(i))
.collect();
let dm_bell = DensityMatrix::from_state_vector(&state_vec);
println!("Bell state |Φ+⟩:");
println!("{}", dm_bell);
println!("Full matrix:");
println!("{:?}", dm_bell);
let is_pure = dm_bell.is_pure(1e-10);
println!("Purity check: {}\n", if is_pure { "✓ Pure" } else { "✗ Mixed" });
results.push(BenchmarkResult {
name: "DM: Bell state".to_string(),
basic_time: std::time::Duration::from_micros(0),
mt_time: std::time::Duration::from_micros(0),
results_match: is_pure,
});
}
pub fn test_noise_channels(results: &mut Vec<BenchmarkResult>) {
print_section("Noise Channel Effects");
let channels: Vec<(&str, NoiseChannel)> = vec![
("Depolarising (p=0.1)", NoiseChannel::depolarising(0.1)),
("Amplitude Damping (γ=0.2)", NoiseChannel::amplitude_damping(0.2)),
("Phase Damping (γ=0.2)", NoiseChannel::phase_damping(0.2)),
("Bit Flip (p=0.1)", NoiseChannel::bit_flip(0.1)),
("Phase Flip (p=0.1)", NoiseChannel::phase_flip(0.1)),
("Bit-Phase Flip (p=0.1)", NoiseChannel::bit_phase_flip(0.1)),
];
let plus_state = vec![
complex!(1.0 / 2.0_f64.sqrt(), 0.0),
complex!(1.0 / 2.0_f64.sqrt(), 0.0),
];
println!("Starting with |+⟩ state: (|0⟩ + |1⟩)/√2\n");
for (name, channel) in channels {
let mut dm = DensityMatrix::from_state_vector(&plus_state);
let initial_purity = dm.purity();
let start = Instant::now();
dm.apply_noise_channel(&channel, 0);
let elapsed = start.elapsed();
let final_purity = dm.purity();
let fidelity = dm.fidelity_with_pure_state(&plus_state);
println!("{:30}", name);
println!(" Purity: {:.4} → {:.4}", initial_purity, final_purity);
println!(" Fidelity with |+⟩: {:.4}", fidelity);
println!(" Probabilities: {:?}", dm.probabilities());
println!(" Time: {:.2}μs\n", elapsed.as_secs_f64() * 1_000_000.0);
let purity_decreased = final_purity <= initial_purity + 1e-10;
results.push(BenchmarkResult {
name: format!("Noise: {}", name),
basic_time: elapsed,
mt_time: elapsed,
results_match: purity_decreased,
});
}
}
pub fn test_noisy_circuit(results: &mut Vec<BenchmarkResult>) {
print_section("Noisy Circuit Simulation");
let mut circuit = QuantumCircuit::new(2);
circuit.h(0).cnot(0, 1);
circuit.compute_with(Runtime::BasicRT);
let state = circuit.state();
let state_vec: Vec<_> = (0..state.size()).map(|i| state.get(i)).collect();
let mut dm = DensityMatrix::from_state_vector(&state_vec);
println!("Bell state before noise:");
println!("{}", dm);
let depol = NoiseChannel::depolarising(0.05);
let start = Instant::now();
dm.apply_noise_channel(&depol, 0);
dm.apply_noise_channel(&depol, 1);
let elapsed = start.elapsed();
println!("Bell state after 5% depolarising on both qubits:");
println!("{}", dm);
let fidelity = dm.fidelity_with_pure_state(&state_vec);
println!("Fidelity with ideal Bell state: {:.4}", fidelity);
println!("Time: {:.2}μs\n", elapsed.as_secs_f64() * 1_000_000.0);
let mut dm2 = DensityMatrix::from_state_vector(&state_vec);
let amp_damp = NoiseChannel::amplitude_damping(0.1);
dm2.apply_noise_channel(&_damp, 0);
dm2.apply_noise_channel(&_damp, 1);
println!("Bell state after 10% amplitude damping on both qubits:");
println!("{}", dm2);
println!("Probabilities show decay towards |00⟩: {:?}", dm2.probabilities());
results.push(BenchmarkResult {
name: "Noisy Bell circuit".to_string(),
basic_time: elapsed,
mt_time: elapsed,
results_match: fidelity > 0.8 && fidelity < 1.0,
});
println!();
print_section("T1/T2 Relaxation Simulation");
let one_state = vec![complex!(0.0, 0.0), complex!(1.0, 0.0)];
let mut dm_t1 = DensityMatrix::from_state_vector(&one_state);
println!("Simulating T1 decay of |1⟩ state:");
println!(" Initial: P(0)={:.4}, P(1)={:.4}", dm_t1.probabilities()[0], dm_t1.probabilities()[1]);
let t1_channel = NoiseChannel::amplitude_damping(0.3);
for step in 1..=5 {
dm_t1.apply_noise_channel(&t1_channel, 0);
println!(
" Step {}: P(0)={:.4}, P(1)={:.4}, Purity={:.4}",
step,
dm_t1.probabilities()[0],
dm_t1.probabilities()[1],
dm_t1.purity()
);
}
let decayed = dm_t1.probabilities()[0] > 0.8;
println!(" Decay complete: {}\n", if decayed { "✓" } else { "✗" });
results.push(BenchmarkResult {
name: "T1 decay simulation".to_string(),
basic_time: std::time::Duration::from_micros(0),
mt_time: std::time::Duration::from_micros(0),
results_match: decayed,
});
}
|
