"""
Quantum Field Theory Module
This module provides quantum field theory functionality including
field quantization, path integrals, and QFT calculations.
"""
import logging
from typing import Dict, Any, List, Optional, Union, Tuple
import asyncio
import numpy as np
logger = logging.getLogger(__name__)
async def quantize_scalar_field(
field_type: str = "free",
spacetime_dimensions: int = 4,
lattice_size: int = 16,
mass: float = 1.0,
coupling: float = 0.1
) -> Dict[str, Any]:
"""
Quantize scalar field theory.
Args:
field_type: Type of field (free, phi4, sine_gordon)
spacetime_dimensions: Number of spacetime dimensions
lattice_size: Lattice size for discretization
mass: Field mass parameter
coupling: Coupling constant
Returns:
Field quantization results
"""
logger.info(f"Quantizing {field_type} scalar field in {spacetime_dimensions}D")
try:
# Create momentum space lattice
if spacetime_dimensions == 2:
# 1+1 dimensions
k_values = np.fft.fftfreq(lattice_size, d=1.0) * 2 * np.pi
dispersion = np.sqrt(k_values**2 + mass**2)
elif spacetime_dimensions == 4:
# 3+1 dimensions (simplified to 1D for computational efficiency)
k_values = np.fft.fftfreq(lattice_size, d=1.0) * 2 * np.pi
dispersion = np.sqrt(k_values**2 + mass**2)
else:
raise ValueError(f"Unsupported spacetime dimensions: {spacetime_dimensions}")
# Calculate zero-point energy
zero_point_energy = 0.5 * np.sum(dispersion)
# Generate field operators (creation/annihilation operators)
creation_ops = {}
annihilation_ops = {}
for i, k in enumerate(k_values):
if abs(k) > 1e-10: # Avoid k=0 issues
creation_ops[k] = f"a_dag_{i}"
annihilation_ops[k] = f"a_{i}"
# Calculate field commutation relations
commutation_relations = _calculate_field_commutators(field_type, lattice_size)
# Calculate Hamiltonian spectrum
n_states = min(100, 2**min(lattice_size//2, 10)) # Limit for computational efficiency
energy_levels = []
for n in range(n_states):
# Energy levels for harmonic oscillator modes
if field_type == "free":
energy = zero_point_energy + np.sum(dispersion) * n
elif field_type == "phi4":
# Include quartic interaction (perturbative)
interaction_energy = coupling * n**2 * lattice_size / 100
energy = zero_point_energy + np.sum(dispersion) * n + interaction_energy
else:
energy = zero_point_energy + np.sum(dispersion) * n
energy_levels.append(energy)
# Calculate correlation functions
correlations = _calculate_field_correlations(field_type, lattice_size, mass, coupling)
return {
'success': True,
'field_type': field_type,
'spacetime_dimensions': spacetime_dimensions,
'lattice_size': lattice_size,
'mass': mass,
'coupling': coupling,
'zero_point_energy': float(zero_point_energy),
'momentum_modes': len(k_values),
'energy_levels': energy_levels[:20], # Return first 20 levels
'ground_state_energy': float(energy_levels[0]),
'first_excited_energy': float(energy_levels[1]) if len(energy_levels) > 1 else None,
'field_correlations': correlations,
'commutation_relations': len(commutation_relations)
}
except Exception as e:
logger.error(f"Error quantizing scalar field: {e}")
return {'success': False, 'error': str(e)}
def _calculate_field_commutators(field_type: str, lattice_size: int) -> Dict[str, str]:
"""Calculate field commutation relations."""
commutators = {}
# Canonical commutation relations [φ(x), π(y)] = iδ(x-y)
for i in range(min(lattice_size, 10)): # Limit for demo
for j in range(min(lattice_size, 10)):
if i == j:
commutators[f"[phi_{i}, pi_{j}]"] = "i * delta"
else:
commutators[f"[phi_{i}, pi_{j}]"] = "0"
return commutators
def _calculate_field_correlations(
field_type: str,
lattice_size: int,
mass: float,
coupling: float
) -> Dict[str, List[float]]:
"""Calculate field correlation functions."""
distances = np.arange(1, min(lattice_size//2, 20))
if field_type == "free":
# Free field correlator: exponential decay
correlations = np.exp(-mass * distances) / np.sqrt(distances)
elif field_type == "phi4":
# φ⁴ theory: modified by interactions
correlations = np.exp(-mass * distances) / np.sqrt(distances) * (1 + coupling * distances)
elif field_type == "sine_gordon":
# Sine-Gordon: soliton contributions
correlations = np.exp(-mass * distances) * np.cos(coupling * distances)
else:
# Default
correlations = np.exp(-mass * distances) / np.sqrt(distances)
return {
'distances': distances.tolist(),
'two_point_function': correlations.tolist(),
'correlation_length': float(1.0 / mass),
'field_type': field_type
}
async def calculate_path_integral(
action_type: str = "scalar",
path_samples: int = 1000,
time_steps: int = 100,
spatial_points: int = 20
) -> Dict[str, Any]:
"""
Calculate path integral using Monte Carlo methods.
Args:
action_type: Type of action (scalar, gauge, fermion)
path_samples: Number of path configurations
time_steps: Temporal discretization
spatial_points: Spatial discretization
Returns:
Path integral calculation results
"""
logger.info(f"Calculating path integral for {action_type} action")
try:
# Generate field configurations
configurations = []
actions = []
for sample in range(path_samples):
if action_type == "scalar":
config = _generate_scalar_configuration(time_steps, spatial_points)
action = _calculate_scalar_action(config)
elif action_type == "gauge":
config = _generate_gauge_configuration(time_steps, spatial_points)
action = _calculate_gauge_action(config)
else:
config = _generate_scalar_configuration(time_steps, spatial_points)
action = _calculate_scalar_action(config)
configurations.append(config)
actions.append(action)
# Calculate observables
mean_action = np.mean(actions)
action_variance = np.var(actions)
# Effective action (averaged over configurations)
effective_action = -np.log(np.mean(np.exp(-np.array(actions))))
# Calculate correlation functions from path integral
correlations = _calculate_path_integral_correlations(configurations)
# Partition function (approximate)
partition_function = np.mean(np.exp(-np.array(actions)))
return {
'success': True,
'action_type': action_type,
'path_samples': path_samples,
'time_steps': time_steps,
'spatial_points': spatial_points,
'mean_action': float(mean_action),
'action_variance': float(action_variance),
'effective_action': float(effective_action),
'partition_function': float(partition_function),
'correlations': correlations,
'configurations_generated': len(configurations)
}
except Exception as e:
logger.error(f"Error in path integral calculation: {e}")
return {'success': False, 'error': str(e)}
def _generate_scalar_configuration(time_steps: int, spatial_points: int) -> np.ndarray:
"""Generate random scalar field configuration."""
# Gaussian random field
config = np.random.normal(0, 1, (time_steps, spatial_points))
# Apply some smoothing to make it more physical
for _ in range(3):
config[1:-1, 1:-1] = (config[1:-1, 1:-1] +
0.1 * (config[:-2, 1:-1] + config[2:, 1:-1] +
config[1:-1, :-2] + config[1:-1, 2:])) / 1.4
return config
def _generate_gauge_configuration(time_steps: int, spatial_points: int) -> np.ndarray:
"""Generate gauge field configuration."""
# U(1) gauge field: random angles
config = np.random.uniform(0, 2*np.pi, (time_steps, spatial_points, 2)) # 2 gauge field components
return config
def _calculate_scalar_action(config: np.ndarray) -> float:
"""Calculate action for scalar field configuration."""
time_steps, spatial_points = config.shape
action = 0.0
# Kinetic term: (∂φ/∂t)²
for t in range(time_steps - 1):
time_derivative = (config[t+1] - config[t])**2
action += 0.5 * np.sum(time_derivative)
# Gradient term: (∇φ)²
for x in range(spatial_points - 1):
spatial_derivative = (config[:, x+1] - config[:, x])**2
action += 0.5 * np.sum(spatial_derivative)
# Mass term: m²φ²
mass_squared = 1.0
action += 0.5 * mass_squared * np.sum(config**2)
# Interaction term: λφ⁴
coupling = 0.1
action += coupling * np.sum(config**4)
return action
def _calculate_gauge_action(config: np.ndarray) -> float:
"""Calculate action for gauge field configuration."""
time_steps, spatial_points, components = config.shape
action = 0.0
# Wilson action: simplified
beta = 1.0 # Gauge coupling
for t in range(time_steps - 1):
for x in range(spatial_points - 1):
# Plaquette: U_μ(x) U_ν(x+μ) U_μ†(x+ν) U_ν†(x)
plaquette = (config[t, x, 0] + config[t+1, x, 1] -
config[t+1, x+1, 0] - config[t, x+1, 1])
# Wilson action: Re[Tr(plaquette)]
action += beta * (1 - np.cos(plaquette))
return action
def _calculate_path_integral_correlations(configurations: List[np.ndarray]) -> Dict[str, List[float]]:
"""Calculate correlation functions from path integral configurations."""
n_configs = len(configurations)
if n_configs == 0:
return {}
# Take first configuration for size reference
time_steps, spatial_points = configurations[0].shape[:2]
# Calculate two-point correlation function
separations = range(1, min(spatial_points//2, 10))
correlations = []
for sep in separations:
corr_sum = 0.0
count = 0
for config in configurations[:min(n_configs, 100)]: # Limit for efficiency
for x in range(spatial_points - sep):
for t in range(time_steps):
corr_sum += config[t, x] * config[t, x + sep]
count += 1
if count > 0:
correlations.append(corr_sum / count)
else:
correlations.append(0.0)
return {
'separations': list(separations),
'two_point_correlations': correlations
}
async def analyze_quantum_anomalies(
theory_type: str = "chiral",
dimensions: int = 4,
gauge_group: str = "U1"
) -> Dict[str, Any]:
"""
Analyze quantum anomalies in field theories.
Args:
theory_type: Type of quantum field theory
dimensions: Spacetime dimensions
gauge_group: Gauge group
Returns:
Anomaly analysis results
"""
logger.info(f"Analyzing quantum anomalies in {theory_type} theory")
try:
anomalies = {}
if theory_type == "chiral":
# Chiral anomaly analysis
if dimensions == 4 and gauge_group == "U1":
# ABJ anomaly coefficient
anomaly_coefficient = 1.0 / (24 * np.pi**2)
anomalies['chiral_anomaly'] = {
'coefficient': anomaly_coefficient,
'type': 'Adler-Bell-Jackiw',
'cancellation': False
}
elif dimensions == 4 and gauge_group == "SU3":
# QCD anomaly
anomaly_coefficient = 3.0 / (32 * np.pi**2) # 3 colors
anomalies['chiral_anomaly'] = {
'coefficient': anomaly_coefficient,
'type': 'QCD',
'cancellation': True # Cancelled by quarks
}
elif theory_type == "gravitational":
# Gravitational anomalies
if dimensions == 4:
anomalies['gravitational_anomaly'] = {
'coefficient': 1.0 / (384 * np.pi**2),
'type': 'Mixed gauge-gravitational',
'cancellation': False
}
elif theory_type == "conformal":
# Conformal anomalies
if dimensions == 4:
# Weyl anomaly
central_charge_a = 1.0 / 90 # Simplified
central_charge_c = 1.0 / 120
anomalies['conformal_anomaly'] = {
'central_charge_a': central_charge_a,
'central_charge_c': central_charge_c,
'type': 'Weyl anomaly'
}
# Calculate anomaly-related observables
if anomalies:
# Anomalous Ward identities
ward_identity_violation = sum(abs(anom.get('coefficient', 0))
for anom in anomalies.values()
if isinstance(anom, dict))
# Index theorem connections
atiyah_singer_index = _calculate_topological_index(theory_type, dimensions)
return {
'success': True,
'theory_type': theory_type,
'dimensions': dimensions,
'gauge_group': gauge_group,
'anomalies': anomalies,
'ward_identity_violation': float(ward_identity_violation),
'topological_index': atiyah_singer_index,
'anomaly_cancellation': all(anom.get('cancellation', False)
for anom in anomalies.values()
if isinstance(anom, dict))
}
else:
return {
'success': True,
'theory_type': theory_type,
'anomalies': {},
'anomaly_free': True
}
except Exception as e:
logger.error(f"Error analyzing anomalies: {e}")
return {'success': False, 'error': str(e)}
def _calculate_topological_index(theory_type: str, dimensions: int) -> int:
"""Calculate topological index for Atiyah-Singer theorem."""
if theory_type == "chiral" and dimensions == 4:
# Simplified index calculation
# In reality, this depends on the specific bundle and operator
return 1
elif theory_type == "gravitational" and dimensions == 4:
# Hirzebruch signature
return 0 # Simplified
else:
return 0
async def renormalization_group_flow(
theory_type: str = "phi4",
coupling_initial: float = 0.1,
energy_scales: int = 50,
beta_function_order: int = 1
) -> Dict[str, Any]:
"""
Calculate renormalization group flow.
Args:
theory_type: Type of field theory
coupling_initial: Initial coupling constant
energy_scales: Number of energy scales to compute
beta_function_order: Order of beta function (1-loop, 2-loop, etc.)
Returns:
RG flow analysis results
"""
logger.info(f"Calculating RG flow for {theory_type} theory")
try:
# Energy scale range (logarithmic)
mu_min, mu_max = 0.1, 10.0
mu_values = np.logspace(np.log10(mu_min), np.log10(mu_max), energy_scales)
# Calculate beta function and run coupling
couplings = [coupling_initial]
beta_values = []
g = coupling_initial
for i in range(1, energy_scales):
# Beta function for different theories
if theory_type == "phi4":
# φ⁴ theory in 4D
beta = _beta_function_phi4(g, beta_function_order)
elif theory_type == "qed":
# QED beta function
beta = _beta_function_qed(g, beta_function_order)
elif theory_type == "qcd":
# QCD beta function
beta = _beta_function_qcd(g, beta_function_order)
else:
# Generic beta function
beta = g**3 / (16 * np.pi**2) # 1-loop generic
beta_values.append(beta)
# RG equation: dg/d(ln μ) = β(g)
dln_mu = np.log(mu_values[i] / mu_values[i-1])
g_new = g + beta * dln_mu
# Ensure coupling remains positive and bounded
g_new = max(0, min(g_new, 5.0))
couplings.append(g_new)
g = g_new
# Find fixed points
fixed_points = _find_fixed_points(beta_values, couplings)
# Calculate critical exponents
critical_exponents = _calculate_critical_exponents(theory_type, fixed_points)
return {
'success': True,
'theory_type': theory_type,
'coupling_initial': coupling_initial,
'energy_scales': mu_values.tolist(),
'couplings': couplings,
'beta_function': beta_values,
'fixed_points': fixed_points,
'critical_exponents': critical_exponents,
'asymptotic_freedom': beta_values[-1] < 0 if beta_values else False,
'landau_pole': any(abs(g) > 4.0 for g in couplings)
}
except Exception as e:
logger.error(f"Error in RG flow calculation: {e}")
return {'success': False, 'error': str(e)}
def _beta_function_phi4(g: float, order: int) -> float:
"""Beta function for φ⁴ theory."""
if order == 1:
# 1-loop
return 3 * g**2 / (16 * np.pi**2)
elif order == 2:
# 2-loop (simplified)
beta_1 = 3 * g**2 / (16 * np.pi**2)
beta_2 = -17 * g**3 / (32 * np.pi**2)**2
return beta_1 + beta_2
else:
return 3 * g**2 / (16 * np.pi**2)
def _beta_function_qed(g: float, order: int) -> float:
"""Beta function for QED."""
if order == 1:
# 1-loop
return g**3 / (12 * np.pi**2)
else:
return g**3 / (12 * np.pi**2)
def _beta_function_qcd(g: float, order: int) -> float:
"""Beta function for QCD."""
n_f = 3 # Number of flavors
if order == 1:
# 1-loop
b0 = (11 * 3 - 2 * n_f) / 3 # 3 colors
return -b0 * g**3 / (16 * np.pi**2)
else:
b0 = (11 * 3 - 2 * n_f) / 3
return -b0 * g**3 / (16 * np.pi**2)
def _find_fixed_points(beta_values: List[float], couplings: List[float]) -> List[Dict[str, float]]:
"""Find fixed points where β(g) = 0."""
fixed_points = []
# Look for sign changes in beta function
for i in range(1, len(beta_values)):
if len(beta_values) > i and beta_values[i-1] * beta_values[i] < 0:
# Sign change indicates fixed point
g_fixed = (couplings[i-1] + couplings[i]) / 2
beta_fixed = (beta_values[i-1] + beta_values[i]) / 2
fixed_points.append({
'coupling': g_fixed,
'beta': beta_fixed,
'stable': beta_values[i] < beta_values[i-1] # Stability criterion
})
# Always include g=0 as trivial fixed point
fixed_points.insert(0, {
'coupling': 0.0,
'beta': 0.0,
'stable': True
})
return fixed_points
def _calculate_critical_exponents(theory_type: str, fixed_points: List[Dict]) -> Dict[str, float]:
"""Calculate critical exponents near fixed points."""
exponents = {}
if theory_type == "phi4":
# φ⁴ theory critical exponents (3D Ising universality)
exponents = {
'nu': 0.630, # Correlation length
'gamma': 1.237, # Susceptibility
'beta': 0.327, # Order parameter
'alpha': 0.110, # Specific heat
'eta': 0.036 # Anomalous dimension
}
elif theory_type == "qcd":
# QCD critical exponents (rough estimates)
exponents = {
'gamma_m': 0.0, # Anomalous mass dimension
'gamma_g': -11/3 # Gauge coupling anomalous dimension
}
else:
# Generic mean-field exponents
exponents = {
'nu': 0.5,
'gamma': 1.0,
'beta': 0.5,
'alpha': 0.0
}
return exponents