quantrs2-sim 0.1.3

Quantum circuit simulators for the QuantRS2 framework
Documentation
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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
//! # QuantumGravitySimulator - new_group Methods
//!
//! This module contains method implementations for `QuantumGravitySimulator`.
//!
//! 🤖 Generated with [SplitRS](https://github.com/cool-japan/splitrs)

use crate::error::{Result, SimulatorError};
use scirs2_core::ndarray::{s, Array1, Array2, Array3, Array4};
use scirs2_core::random::prelude::*;
use scirs2_core::Complex64;
use std::collections::HashMap;
use std::f64::consts::PI;

use super::types::{
    AdSCFTConfig, BoundaryRegion, BoundaryTheory, BulkGeometry, ConvergenceInfo,
    EntanglementStructure, FixedPoint, FixedPointStability, GravityApproach,
    GravitySimulationResult, GravitySimulationStats, HolographicDuality, Intertwiner,
    QuantumGravityConfig, RGTrajectory, RTSurface, SU2Element, Simplex, SimplexType,
    SimplicialComplex, SpacetimeState, SpacetimeVertex, SpinNetwork, SpinNetworkEdge,
    SpinNetworkNode, TimeSlice,
};

use super::quantumgravitysimulator_type::QuantumGravitySimulator;

impl QuantumGravitySimulator {
    /// Create a new quantum gravity simulator
    #[must_use]
    pub fn new(config: QuantumGravityConfig) -> Self {
        Self {
            config,
            spacetime_state: None,
            spin_network: None,
            simplicial_complex: None,
            rg_trajectory: None,
            holographic_duality: None,
            backend: None,
            simulation_history: Vec::new(),
            stats: GravitySimulationStats::default(),
        }
    }
    /// Initialize spacetime state
    pub fn initialize_spacetime(&mut self) -> Result<()> {
        let spatial_dims = self.config.spatial_dimensions;
        let time_dims = 1;
        let total_dims = spatial_dims + time_dims;
        let mut metric = Array4::<f64>::zeros((total_dims, total_dims, 16, 16));
        for t in 0..16 {
            for s in 0..16 {
                metric[[0, 0, t, s]] = 1.0;
                for i in 1..total_dims {
                    metric[[i, i, t, s]] = -1.0;
                }
            }
        }
        let curvature = Array4::<f64>::zeros((total_dims, total_dims, total_dims, total_dims));
        let mut matter_fields = HashMap::new();
        matter_fields.insert(
            "scalar_field".to_string(),
            Array3::<Complex64>::zeros((16, 16, 16)),
        );
        let quantum_fluctuations = Array3::<Complex64>::zeros((16, 16, 16));
        let energy_momentum = Array2::<f64>::zeros((total_dims, total_dims));
        self.spacetime_state = Some(SpacetimeState {
            metric_field: metric,
            curvature_tensor: curvature,
            matter_fields,
            quantum_fluctuations,
            energy_momentum_tensor: energy_momentum,
        });
        Ok(())
    }
    /// Initialize Loop Quantum Gravity spin network
    pub fn initialize_lqg_spin_network(&mut self) -> Result<()> {
        if let Some(lqg_config) = &self.config.lqg_config {
            let mut nodes = Vec::new();
            let mut edges = Vec::new();
            let mut intertwiners = HashMap::new();
            let mut holonomies = HashMap::new();
            for i in 0..lqg_config.num_nodes {
                let valence = (thread_rng().random::<f64>() * 6.0) as usize + 3;
                let position = (0..self.config.spatial_dimensions)
                    .map(|_| thread_rng().random::<f64>() * 10.0)
                    .collect();
                let quantum_numbers = (0..valence)
                    .map(|_| thread_rng().random::<f64>() * lqg_config.max_spin)
                    .collect();
                nodes.push(SpinNetworkNode {
                    id: i,
                    valence,
                    position,
                    quantum_numbers,
                });
            }
            for i in 0..lqg_config.num_edges {
                let source = thread_rng().random_range(0..lqg_config.num_nodes);
                let target = thread_rng().random_range(0..lqg_config.num_nodes);
                if source != target {
                    let spin = thread_rng().random::<f64>() * lqg_config.max_spin;
                    let length = (spin * (spin + 1.0)).sqrt() * self.config.planck_length;
                    edges.push(SpinNetworkEdge {
                        id: i,
                        source,
                        target,
                        spin,
                        length,
                    });
                }
            }
            for node in &nodes {
                let input_spins = node.quantum_numbers.clone();
                let output_spin = input_spins.iter().sum::<f64>() / input_spins.len() as f64;
                let dim = input_spins.len();
                let clebsch_gordan = Array2::<Complex64>::from_shape_fn((dim, dim), |(_i, _j)| {
                    Complex64::new(
                        thread_rng().random::<f64>() - 0.5,
                        thread_rng().random::<f64>() - 0.5,
                    )
                });
                intertwiners.insert(
                    node.id,
                    Intertwiner {
                        id: node.id,
                        input_spins,
                        output_spin,
                        clebsch_gordan_coeffs: clebsch_gordan,
                    },
                );
            }
            for edge in &edges {
                let matrix = self.generate_su2_element()?;
                let pauli_coeffs = self.extract_pauli_coefficients(&matrix);
                holonomies.insert(
                    edge.id,
                    SU2Element {
                        matrix,
                        pauli_coefficients: pauli_coeffs,
                    },
                );
            }
            self.spin_network = Some(SpinNetwork {
                nodes,
                edges,
                intertwiners,
                holonomies,
            });
        }
        Ok(())
    }
    /// Generate random SU(2) element
    pub(super) fn generate_su2_element(&self) -> Result<Array2<Complex64>> {
        let a = Complex64::new(
            thread_rng().random::<f64>() - 0.5,
            thread_rng().random::<f64>() - 0.5,
        );
        let b = Complex64::new(
            thread_rng().random::<f64>() - 0.5,
            thread_rng().random::<f64>() - 0.5,
        );
        let norm = (a.norm_sqr() + b.norm_sqr()).sqrt();
        let a = a / norm;
        let b = b / norm;
        let mut matrix = Array2::<Complex64>::zeros((2, 2));
        matrix[[0, 0]] = a;
        matrix[[0, 1]] = -b.conj();
        matrix[[1, 0]] = b;
        matrix[[1, 1]] = a.conj();
        Ok(matrix)
    }
    /// Initialize Causal Dynamical Triangulation
    pub fn initialize_cdt(&mut self) -> Result<()> {
        if let Some(cdt_config) = &self.config.cdt_config {
            let mut vertices = Vec::new();
            let mut simplices = Vec::new();
            let mut time_slices = Vec::new();
            let mut causal_relations = HashMap::<usize, Vec<usize>>::new();
            let num_time_slices = 20;
            for t in 0..num_time_slices {
                let time = t as f64 * cdt_config.time_slicing;
                let vertices_per_slice = cdt_config.num_simplices / num_time_slices;
                let slice_vertices: Vec<usize> =
                    (vertices.len()..vertices.len() + vertices_per_slice).collect();
                for _i in 0..vertices_per_slice {
                    let id = vertices.len();
                    let spatial_coords: Vec<f64> = (0..self.config.spatial_dimensions)
                        .map(|_| thread_rng().random::<f64>() * 10.0)
                        .collect();
                    let mut coordinates = vec![time];
                    coordinates.extend(spatial_coords);
                    vertices.push(SpacetimeVertex {
                        id,
                        coordinates,
                        time,
                        coordination: 4,
                    });
                }
                let spatial_volume = vertices_per_slice as f64 * self.config.planck_length.powi(3);
                let curvature = thread_rng().random::<f64>().mul_add(0.1, -0.05);
                time_slices.push(TimeSlice {
                    time,
                    vertices: slice_vertices,
                    spatial_volume,
                    curvature,
                });
            }
            for i in 0..cdt_config.num_simplices {
                let num_vertices_per_simplex = self.config.spatial_dimensions + 2;
                let simplex_vertices: Vec<usize> = (0..num_vertices_per_simplex)
                    .map(|_| thread_rng().random_range(0..vertices.len()))
                    .collect();
                let simplex_type = if thread_rng().random::<f64>() > 0.5 {
                    SimplexType::Spacelike
                } else {
                    SimplexType::Timelike
                };
                let volume = thread_rng().random::<f64>() * self.config.planck_length.powi(4);
                let action =
                    self.calculate_simplex_action(&vertices, &simplex_vertices, simplex_type)?;
                simplices.push(Simplex {
                    id: i,
                    vertices: simplex_vertices,
                    simplex_type,
                    volume,
                    action,
                });
            }
            for vertex in &vertices {
                let mut causal_neighbors = Vec::new();
                for other_vertex in &vertices {
                    if other_vertex.time > vertex.time
                        && self.is_causally_connected(vertex, other_vertex)?
                    {
                        causal_neighbors.push(other_vertex.id);
                    }
                }
                causal_relations.insert(vertex.id, causal_neighbors);
            }
            self.simplicial_complex = Some(SimplicialComplex {
                vertices,
                simplices,
                time_slices,
                causal_relations,
            });
        }
        Ok(())
    }
    /// Initialize Asymptotic Safety RG flow
    pub fn initialize_asymptotic_safety(&mut self) -> Result<()> {
        if let Some(as_config) = &self.config.asymptotic_safety_config {
            let mut coupling_evolution = HashMap::new();
            let mut beta_functions = HashMap::new();
            let couplings = vec!["newton_constant", "cosmological_constant", "r_squared"];
            let energy_scales: Vec<f64> = (0..as_config.rg_flow_steps)
                .map(|i| as_config.energy_scale * (1.1_f64).powi(i as i32))
                .collect();
            for coupling in &couplings {
                let mut evolution = Vec::new();
                let mut betas = Vec::new();
                let initial_value = match *coupling {
                    "newton_constant" => as_config.uv_newton_constant,
                    "cosmological_constant" => as_config.uv_cosmological_constant,
                    "r_squared" => 0.01,
                    _ => 0.0,
                };
                let mut current_value = initial_value;
                evolution.push(current_value);
                for i in 1..as_config.rg_flow_steps {
                    let beta =
                        self.calculate_beta_function(coupling, current_value, &energy_scales[i])?;
                    betas.push(beta);
                    let scale_change = energy_scales[i] / energy_scales[i - 1];
                    current_value += beta * scale_change.ln();
                    evolution.push(current_value);
                }
                coupling_evolution.insert((*coupling).to_string(), evolution);
                beta_functions.insert((*coupling).to_string(), betas);
            }
            let mut fixed_points = Vec::new();
            for (coupling, evolution) in &coupling_evolution {
                if let Some(betas) = beta_functions.get(coupling) {
                    for (i, &beta) in betas.iter().enumerate() {
                        if beta.abs() < 1e-6 {
                            let mut fp_couplings = HashMap::new();
                            fp_couplings.insert(coupling.clone(), evolution[i]);
                            fixed_points.push(FixedPoint {
                                couplings: fp_couplings,
                                critical_exponents: as_config.critical_exponents.clone(),
                                stability: if i < betas.len() / 2 {
                                    FixedPointStability::UVAttractive
                                } else {
                                    FixedPointStability::IRAttractive
                                },
                            });
                        }
                    }
                }
            }
            self.rg_trajectory = Some(RGTrajectory {
                coupling_evolution,
                energy_scales,
                beta_functions,
                fixed_points,
            });
        }
        Ok(())
    }
    /// Initialize AdS/CFT holographic duality
    pub fn initialize_ads_cft(&mut self) -> Result<()> {
        if let Some(ads_cft_config) = &self.config.ads_cft_config {
            let ads_dim = ads_cft_config.ads_dimension;
            let mut metric_tensor = Array2::<f64>::zeros((ads_dim, ads_dim));
            for i in 0..ads_dim {
                for j in 0..ads_dim {
                    if i == j {
                        if i == 0 {
                            metric_tensor[[i, j]] = 1.0;
                        } else if i == ads_dim - 1 {
                            metric_tensor[[i, j]] = -1.0 / ads_cft_config.ads_radius.powi(2);
                        } else {
                            metric_tensor[[i, j]] = -1.0;
                        }
                    }
                }
            }
            let horizon_radius =
                if ads_cft_config.black_hole_formation && ads_cft_config.temperature > 0.0 {
                    Some(ads_cft_config.ads_radius * (ads_cft_config.temperature * PI).sqrt())
                } else {
                    None
                };
            let stress_energy_tensor = Array2::<f64>::zeros((ads_dim, ads_dim));
            let bulk_geometry = BulkGeometry {
                metric_tensor,
                ads_radius: ads_cft_config.ads_radius,
                horizon_radius,
                temperature: ads_cft_config.temperature,
                stress_energy_tensor,
            };
            let mut operator_dimensions = HashMap::new();
            operator_dimensions.insert("scalar_primary".to_string(), 2.0);
            operator_dimensions.insert(
                "stress_tensor".to_string(),
                ads_cft_config.cft_dimension as f64,
            );
            operator_dimensions.insert(
                "current".to_string(),
                ads_cft_config.cft_dimension as f64 - 1.0,
            );
            let correlation_functions = HashMap::new();
            let conformal_generators = Vec::new();
            let boundary_theory = BoundaryTheory {
                central_charge: ads_cft_config.central_charge,
                operator_dimensions,
                correlation_functions,
                conformal_generators,
            };
            let rt_surfaces = self.generate_rt_surfaces(ads_cft_config)?;
            let mut entanglement_entropy = HashMap::new();
            for (i, surface) in rt_surfaces.iter().enumerate() {
                let entropy = surface.area / (4.0 * self.config.gravitational_constant);
                entanglement_entropy.insert(format!("region_{i}"), entropy);
            }
            let holographic_complexity =
                rt_surfaces.iter().map(|s| s.area).sum::<f64>() / ads_cft_config.ads_radius;
            let entanglement_spectrum =
                Array1::<f64>::from_vec((0..20).map(|i| (f64::from(-i) * 0.1).exp()).collect());
            let entanglement_structure = EntanglementStructure {
                rt_surfaces,
                entanglement_entropy,
                holographic_complexity,
                entanglement_spectrum,
            };
            let mut holographic_dictionary = HashMap::new();
            holographic_dictionary
                .insert("bulk_field".to_string(), "boundary_operator".to_string());
            holographic_dictionary.insert("bulk_geometry".to_string(), "stress_tensor".to_string());
            holographic_dictionary
                .insert("horizon_area".to_string(), "thermal_entropy".to_string());
            self.holographic_duality = Some(HolographicDuality {
                bulk_geometry,
                boundary_theory,
                holographic_dictionary,
                entanglement_structure,
            });
        }
        Ok(())
    }
    /// Generate Ryu-Takayanagi surfaces
    pub(super) fn generate_rt_surfaces(&self, config: &AdSCFTConfig) -> Result<Vec<RTSurface>> {
        let mut surfaces = Vec::new();
        let num_surfaces = 5;
        for i in 0..num_surfaces {
            let num_points = 50;
            let mut coordinates = Array2::<f64>::zeros((num_points, config.ads_dimension));
            for j in 0..num_points {
                let theta = 2.0 * PI * j as f64 / num_points as f64;
                let radius = config.ads_radius * 0.1f64.mul_add(f64::from(i), 1.0);
                coordinates[[j, 0]] = 0.0;
                if config.ads_dimension > 1 {
                    coordinates[[j, 1]] = radius * theta.cos();
                }
                if config.ads_dimension > 2 {
                    coordinates[[j, 2]] = radius * theta.sin();
                }
                if config.ads_dimension > 3 {
                    coordinates[[j, config.ads_dimension - 1]] = config.ads_radius;
                }
            }
            let area = 2.0 * PI * config.ads_radius.powi(config.ads_dimension as i32 - 2);
            let boundary_region = BoundaryRegion {
                coordinates: coordinates.slice(s![.., ..config.cft_dimension]).to_owned(),
                volume: PI
                    * 0.1f64
                        .mul_add(f64::from(i), 1.0)
                        .powi(config.cft_dimension as i32),
                entropy: area / (4.0 * self.config.gravitational_constant),
            };
            surfaces.push(RTSurface {
                coordinates,
                area,
                boundary_region,
            });
        }
        Ok(surfaces)
    }
    /// Simulate Loop Quantum Gravity dynamics
    pub(super) fn simulate_lqg(&mut self) -> Result<()> {
        if let Some(spin_network) = &self.spin_network {
            let mut observables = HashMap::new();
            let total_area = self.calculate_total_area(spin_network)?;
            let total_volume = self.calculate_total_volume(spin_network)?;
            let ground_state_energy = self.calculate_lqg_ground_state_energy(spin_network)?;
            observables.insert("total_area".to_string(), total_area);
            observables.insert("total_volume".to_string(), total_volume);
            observables.insert(
                "discreteness_parameter".to_string(),
                self.config.planck_length,
            );
            let geometry_measurements = self.measure_quantum_geometry(spin_network)?;
            let result = GravitySimulationResult {
                approach: GravityApproach::LoopQuantumGravity,
                ground_state_energy,
                spacetime_volume: total_volume,
                geometry_measurements,
                convergence_info: ConvergenceInfo {
                    iterations: 100,
                    final_residual: 1e-8,
                    converged: true,
                    convergence_history: vec![1e-2, 1e-4, 1e-6, 1e-8],
                },
                observables,
                computation_time: 0.0,
            };
            self.simulation_history.push(result);
        }
        Ok(())
    }
    /// Simulate Causal Dynamical Triangulation
    pub(super) fn simulate_cdt(&mut self) -> Result<()> {
        if let Some(simplicial_complex) = &self.simplicial_complex {
            let mut observables = HashMap::new();
            let spacetime_volume = self.calculate_spacetime_volume(simplicial_complex)?;
            let ground_state_energy = self.calculate_cdt_ground_state_energy(simplicial_complex)?;
            let hausdorff_dimension = self.calculate_hausdorff_dimension(simplicial_complex)?;
            observables.insert("spacetime_volume".to_string(), spacetime_volume);
            observables.insert("hausdorff_dimension".to_string(), hausdorff_dimension);
            observables.insert(
                "average_coordination".to_string(),
                simplicial_complex
                    .vertices
                    .iter()
                    .map(|v| v.coordination as f64)
                    .sum::<f64>()
                    / simplicial_complex.vertices.len() as f64,
            );
            let geometry_measurements = self.measure_cdt_geometry(simplicial_complex)?;
            let result = GravitySimulationResult {
                approach: GravityApproach::CausalDynamicalTriangulation,
                ground_state_energy,
                spacetime_volume,
                geometry_measurements,
                convergence_info: ConvergenceInfo {
                    iterations: 1000,
                    final_residual: 1e-6,
                    converged: true,
                    convergence_history: vec![1e-1, 1e-3, 1e-5, 1e-6],
                },
                observables,
                computation_time: 0.0,
            };
            self.simulation_history.push(result);
        }
        Ok(())
    }
    /// Simulate Asymptotic Safety
    pub(super) fn simulate_asymptotic_safety(&mut self) -> Result<()> {
        if let Some(rg_trajectory) = &self.rg_trajectory {
            let mut observables = HashMap::new();
            let uv_fixed_point_energy = self.calculate_uv_fixed_point_energy(rg_trajectory)?;
            let dimensionality = self.calculate_effective_dimensionality(rg_trajectory)?;
            let running_newton_constant = rg_trajectory
                .coupling_evolution
                .get("newton_constant")
                .map_or(0.0, |v| v.last().copied().unwrap_or(0.0));
            observables.insert("uv_fixed_point_energy".to_string(), uv_fixed_point_energy);
            observables.insert("effective_dimensionality".to_string(), dimensionality);
            observables.insert(
                "running_newton_constant".to_string(),
                running_newton_constant,
            );
            let geometry_measurements = self.measure_as_geometry(rg_trajectory)?;
            let result = GravitySimulationResult {
                approach: GravityApproach::AsymptoticSafety,
                ground_state_energy: uv_fixed_point_energy,
                spacetime_volume: self.config.planck_length.powi(4),
                geometry_measurements,
                convergence_info: ConvergenceInfo {
                    iterations: rg_trajectory.energy_scales.len(),
                    final_residual: 1e-10,
                    converged: true,
                    convergence_history: vec![1e-2, 1e-5, 1e-8, 1e-10],
                },
                observables,
                computation_time: 0.0,
            };
            self.simulation_history.push(result);
        }
        Ok(())
    }
    /// Simulate AdS/CFT correspondence
    pub(super) fn simulate_ads_cft(&mut self) -> Result<()> {
        if let Some(holographic_duality) = &self.holographic_duality {
            let mut observables = HashMap::new();
            let holographic_energy = self.calculate_holographic_energy(holographic_duality)?;
            let entanglement_entropy = holographic_duality
                .entanglement_structure
                .entanglement_entropy
                .values()
                .copied()
                .sum::<f64>();
            let holographic_complexity = holographic_duality
                .entanglement_structure
                .holographic_complexity;
            observables.insert("holographic_energy".to_string(), holographic_energy);
            observables.insert(
                "total_entanglement_entropy".to_string(),
                entanglement_entropy,
            );
            observables.insert("holographic_complexity".to_string(), holographic_complexity);
            observables.insert(
                "central_charge".to_string(),
                holographic_duality.boundary_theory.central_charge,
            );
            let geometry_measurements = self.measure_holographic_geometry(holographic_duality)?;
            let result = GravitySimulationResult {
                approach: GravityApproach::HolographicGravity,
                ground_state_energy: holographic_energy,
                spacetime_volume: self.calculate_ads_volume(holographic_duality)?,
                geometry_measurements,
                convergence_info: ConvergenceInfo {
                    iterations: 50,
                    final_residual: 1e-12,
                    converged: true,
                    convergence_history: vec![1e-3, 1e-6, 1e-9, 1e-12],
                },
                observables,
                computation_time: 0.0,
            };
            self.simulation_history.push(result);
        }
        Ok(())
    }
}