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C4-2-formal: 波函数坍缩的信息理论推论的形式化规范

机器验证元数据

type: corollary
verification: machine_ready
dependencies: ["A1-formal.md", "C4-1-formal.md", "T3-2-formal.md", "D1-8-formal.md"]
verification_points:
- information_gain_calculation
- measurement_operator_optimization
- collapse_probability_verification
- post_measurement_state_uniqueness
- measurement_backaction_necessity
- information_causality_check

核心推论

推论 C4-2(波函数坍缩的信息理论)

WavefunctionCollapseInformationTheory : Prop ≡
∀ψ : QuantumState, M : MeasurementOperator, O : Observer .
measurement(M, ψ) ↔ information_gain(O, ψ) ∧
collapse_outcome = argmax_{n} information_content(n) ∧
optimal_basis(M) = phi_representation_basis

where
MeasurementOperator : Type = {
operators : List[Matrix[ℂ]],
completeness : ∑_n M_n† M_n = I,
orthogonality : M_i M_j = δ_{ij} M_i
}

InformationGain : Type = {
before : ℝ, // Entropy before measurement
after : ℝ, // Entropy after measurement
gain : ℝ, // after - before
positive : gain ≥ 0
}

形式化组件

1. 测量的信息论表示

MeasurementAsInformation : QuantumState → MeasurementOperator → InformationGain ≡
λψ, M .
let ρ_before = |ψ⟩⟨ψ| in
let outcomes = measure_probabilities(ψ, M) in
let ρ_after = ∑_n p_n |n⟩_φ⟨n|_φ in
InformationGain {
before = von_neumann_entropy(ρ_before),
after = von_neumann_entropy(ρ_after),
gain = shannon_entropy(outcomes),
positive = true // By construction
}

MeasureProbabilities : QuantumState → MeasurementOperator → List[ℝ] ≡
λψ, M .
[|⟨n|_φ|ψ⟩|² for n in valid_phi_representations]

2. φ-优化测量算子

PhiOptimalMeasurement : Type ≡
record {
basis_states : List[PhiBasisState]
projectors : List[ProjectionOperator]
completeness : ∑_n P_n = I
orthogonality : P_i P_j = δ_{ij} P_i
phi_structured : ∀n . P_n = |n⟩_φ⟨n|_φ
}

ConstructPhiMeasurement : ℕ → PhiOptimalMeasurement ≡
λdimension .
let valid_states = generate_valid_phi_states(dimension) in
let projectors = [|n⟩_φ⟨n|_φ for n in valid_states] in
PhiOptimalMeasurement {
basis_states = valid_states,
projectors = projectors,
completeness = verified_by_construction,
orthogonality = verified_by_construction,
phi_structured = true
}

3. 信息增益最大化

InformationMaximization : MeasurementOperator → QuantumState → ℝ ≡
λM, ψ .
let probabilities = measure_probabilities(ψ, M) in
shannon_entropy(probabilities)

OptimalMeasurementBasis : QuantumState → Set[BasisState] ≡
λψ .
argmax_{basis} information_gain(measure_in_basis(basis, ψ))

ProofOfPhiOptimality : Prop ≡
∀ψ : QuantumState .
optimal_measurement_basis(ψ) ⊆ phi_basis_states

// This holds because φ-basis maximizes distinguishability under no-11 constraint

4. 坍缩动力学

CollapseEvolution : QuantumState → MeasurementResult → QuantumState ≡
λψ, n .
let M_n = |n⟩_φ⟨n|_φ in
let ψ_unnormalized = M_n|ψ⟩ in
let norm = √⟨ψ|M_n†M_n|ψ⟩ in
ψ_unnormalized / norm

CollapseProbability : QuantumState → ℕ → ℝ ≡
λψ, n .
|⟨n|_φ|ψ⟩|²

PostMeasurementState : QuantumState → MeasurementResult → DensityMatrix ≡
λψ, n .
|n⟩_φ⟨n|_φ // Pure state after measurement

5. 测量反作用

MeasurementBackaction : DensityMatrix → MeasurementOperator → DensityMatrix ≡
λρ, M .
let outcomes = [M_n ρ M_n† for n in measurement_outcomes] in
∑_n outcomes[n]

BackactionMagnitude : DensityMatrix → DensityMatrix → ℝ ≡
λρ_before, ρ_after .
trace_distance(ρ_before, ρ_after)

NoFreeInformation : Prop ≡
∀ρ, M . information_gain(ρ, M) > 0 →
backaction_magnitude(ρ, measurement_backaction(ρ, M)) > 0

6. 信息效率度量

InformationEfficiency : MeasurementBasis → ℕ → ℝ ≡
λbasis, dimension .
let max_entropy = log(dimension) in
let actual_entropy = average_measurement_entropy(basis) in
actual_entropy / max_entropy

PhiBasisEfficiency : ℕ → ℝ ≡
λdimension .
let phi_basis = construct_phi_measurement(dimension) in
information_efficiency(phi_basis.basis_states, dimension)

EfficiencyTheorem : Prop ≡
∀dimension, basis .
information_efficiency(phi_basis, dimension) ≥
information_efficiency(basis, dimension)

算法规范

测量模拟算法

QuantumMeasurementSimulation : Algorithm ≡
Input: ψ : QuantumState, measurement_basis : MeasurementBasis
Output: (result : MeasurementResult, ψ_after : QuantumState, info_gain :)

Process:
1. # Calculate initial entropy
2. ρ_initial = |ψ⟩⟨ψ|
3. S_initial = von_neumann_entropy(ρ_initial) # = 0 for pure state

4. # Calculate measurement probabilities
5. probabilities = []
6. for basis_state in measurement_basis:
p = |⟨basis_state|ψ⟩|²
probabilities.append(p)

7. # Sample measurement outcome
8. result = sample_from_distribution(probabilities)

9. # Calculate collapsed state
10. ψ_after = measurement_basis[result]

11. # Calculate information gain
12. info_gain = -∑_i p_i log(p_i) # Shannon entropy of outcome distribution

13. return (result, ψ_after, info_gain)

Invariants:
- ∑ probabilities = 1
- |ψ_after⟩ is normalized
- info_gain ≥ 0

φ-最优测量构造算法

ConstructOptimalPhiMeasurement : Algorithm ≡
Input: dimension :
Output: measurement : PhiOptimalMeasurement

Process:
1. φ = (1 +5) / 2
2. valid_indices = []
3.
4. # Generate valid φ-representation indices (no consecutive 1s)
5. for i in range(dimension):
if is_valid_phi_representation(i):
valid_indices.append(i)

6. # Construct basis states
7. basis_states = []
8. for idx in valid_indices:
state = zeros(dimension)
state[idx] = 1
basis_states.append(state)

9. # Construct projectors
10. projectors = []
11. for state in basis_states:
P = outer_product(state, state)
projectors.append(P)

12. # Verify completeness (may need padding for non-square dimensions)
13. if len(projectors) < dimension:
# Add projectors onto subspace orthogonal to φ-basis
add_completion_projectors(projectors, dimension)

14. return PhiOptimalMeasurement(basis_states, projectors)

信息因果性验证算法

VerifyInformationCausality : Algorithm ≡
Input: measurement_sequence : List[(time, location, result)]
Output: causality_preserved : Bool

Process:
1. # Sort measurements by time
2. sorted_measurements = sort_by_time(measurement_sequence)
3.
4. # Check light-cone constraints
5. for i in range(len(sorted_measurements) - 1):
m1 = sorted_measurements[i]
m2 = sorted_measurements[i + 1]

Δt = m2.time - m1.time
Δx = distance(m1.location, m2.location)

# Information cannot propagate faster than light
if Δx > c * Δt:
# Check if measurements are correlated
if are_correlated(m1.result, m2.result):
return False # Causality violation

6. return True # All measurements respect causality

数学性质验证

性质1:Born规则的信息论推导

BornRuleDerivation : Prop ≡
∀ψ : QuantumState, n : MeasurementOutcome .
P(n|ψ) = |⟨n|ψ⟩|² ↔
P(n|ψ) = argmax_{probability_distribution} expected_information_gain

性质2:量子Zeno效应

QuantumZenoEffect : Prop ≡
∀ψ : QuantumState, H : Hamiltonian, τ : ℝ⁺ .
lim_{τ→0} evolution_under_repeated_measurement(ψ, H, τ) = ψ

where repeated measurement happens at intervals τ

性质3:测量不可克隆

MeasurementNoCloning : Prop ≡
¬∃M : MeasurementOperator .
∀ψ . measurement(M, ψ) yields complete_information(ψ) ∧
post_measurement_state = ψ

验证检查点

1. 信息增益计算验证

def verify_information_gain_calculation(quantum_state, measurement_basis):
"""验证信息增益计算的正确性"""
# Calculate probabilities
probabilities = []
for basis_state in measurement_basis:
p = abs(inner_product(basis_state, quantum_state))**2
probabilities.append(p)

# Verify normalization
assert abs(sum(probabilities) - 1.0) < 1e-10

# Calculate Shannon entropy (information gain)
info_gain = 0
for p in probabilities:
if p > 0:
info_gain -= p * np.log2(p)

# Information gain should be non-negative
assert info_gain >= 0

# For uniform superposition, should be maximal
if is_uniform_superposition(quantum_state):
expected_max = np.log2(len([p for p in probabilities if p > 0]))
assert abs(info_gain - expected_max) < 1e-6

return info_gain

2. 测量算子优化验证

def verify_measurement_operator_optimization(dimension):
"""验证φ-基测量的最优性"""
# Construct φ-basis measurement
phi_measurement = construct_optimal_phi_measurement(dimension)

# Construct alternative measurement (e.g., computational basis)
comp_measurement = construct_computational_measurement(dimension)

# Test on various quantum states
test_states = generate_test_states(dimension, num_states=100)

phi_efficiency_sum = 0
comp_efficiency_sum = 0

for state in test_states:
phi_info = calculate_information_gain(state, phi_measurement)
comp_info = calculate_information_gain(state, comp_measurement)

phi_efficiency_sum += phi_info
comp_efficiency_sum += comp_info

# φ-basis should have higher average information efficiency
assert phi_efficiency_sum >= comp_efficiency_sum

return True

3. 坍缩概率验证

def verify_collapse_probability_verification(quantum_state, measurement_basis):
"""验证坍缩概率的正确性"""
probabilities = []

for i, basis_state in enumerate(measurement_basis):
# Calculate probability using Born rule
amplitude = inner_product(basis_state, quantum_state)
probability = abs(amplitude)**2
probabilities.append(probability)

# Verify probability bounds
assert 0 <= probability <= 1

# Verify collapse state
if probability > 0:
collapsed_state = collapse_evolution(quantum_state, i)
# Collapsed state should be the basis state
assert np.allclose(collapsed_state, basis_state)

# Verify probability normalization
total_probability = sum(probabilities)
assert abs(total_probability - 1.0) < 1e-10

return probabilities

4. 后测量态唯一性验证

def verify_post_measurement_state_uniqueness(quantum_state, measurement_result):
"""验证测量后状态的唯一性"""
# Apply measurement
post_state_1 = collapse_evolution(quantum_state, measurement_result)

# Apply same measurement again
post_state_2 = collapse_evolution(post_state_1, measurement_result)

# Should get same state (eigenstate property)
assert np.allclose(post_state_1, post_state_2)

# Verify it's a pure state
density_matrix = np.outer(post_state_1, np.conj(post_state_1))
purity = np.trace(density_matrix @ density_matrix)
assert abs(purity - 1.0) < 1e-10

return True

5. 测量反作用必然性验证

def verify_measurement_backaction_necessity(quantum_state, measurement):
"""验证测量反作用的必然性"""
# Initial state
rho_initial = np.outer(quantum_state, np.conj(quantum_state))

# Apply measurement
rho_after = measurement_backaction(rho_initial, measurement)

# Calculate information gain
info_gain = calculate_information_gain(quantum_state, measurement)

# Calculate backaction magnitude
backaction = trace_distance(rho_initial, rho_after)

# If information was gained, there must be backaction
if info_gain > 1e-10:
assert backaction > 1e-10, "No free information: backaction required"

# Verify backaction is bounded
assert backaction <= 2.0 # Maximum trace distance

return True

实用函数

def simulate_quantum_measurement(quantum_state, measurement_type='phi'):
"""模拟量子测量过程"""
if measurement_type == 'phi':
measurement = construct_optimal_phi_measurement(len(quantum_state))
else:
measurement = construct_measurement_basis(len(quantum_state), measurement_type)

# Calculate probabilities and sample outcome
probabilities = calculate_probabilities(quantum_state, measurement)
outcome = np.random.choice(len(probabilities), p=probabilities)

# Get collapsed state
collapsed_state = measurement.basis_states[outcome]

# Calculate information gain
info_gain = shannon_entropy(probabilities)

return {
'outcome': outcome,
'collapsed_state': collapsed_state,
'information_gain': info_gain,
'probabilities': probabilities
}

def compare_measurement_bases(quantum_state, bases_list):
"""比较不同测量基的信息效率"""
results = {}

for basis_name, basis in bases_list:
info_gain = calculate_information_gain(quantum_state, basis)
distinguishability = calculate_distinguishability(basis)

results[basis_name] = {
'information_gain': info_gain,
'distinguishability': distinguishability,
'efficiency': info_gain / np.log2(len(basis))
}

return results

与其他理论的联系

依赖关系

  • A1: 自指完备系统必然熵增(基础公理)
  • C4-1: 量子经典化(退相干基础)
  • T3-2: 量子测量定理(测量形式)
  • D1-8: φ-表示定义(最优基)

支撑的理论

  • 为C4-3(测量装置涌现)提供信息论基础
  • 为量子信息论提供新诠释
  • 为量子密码学提供理论支撑
形式化规范:波函数坍缩等价于最优信息提取过程\boxed{\text{形式化规范:波函数坍缩等价于最优信息提取过程}}