gaussian-mean-width-identification-capacity

name	gaussian-mean-width-identification-capacity
description	Single-letter efficiently computable strong converse bound on classical identification capacity of quantum channels via Gaussian mean width analysis
category	quantum

Gaussian Mean Width Identification Capacity Bound

Methodology

Single-letter strong converse bound on classical identification capacity of quantum channels using geometric analysis of output space.

Key Techniques

1. σ-Euclidean geometry: Product state-weighted geometry for channel output space
2. Sudakov's inequality: Bounds covering numbers via Gaussian mean widths
3. Semidefinite representation: Bound admits efficient SDP computation
4. Channel improvements: Improves bounds for depolarizing, Pauli, erasure, and amplitude damping channels

Mathematical Framework

• Trace-distance separation controlled by Euclidean covering estimates
• Exponential growth governed by operator norm of single-letter positive operator
• Optimization over weighting states yields tight bounds

Activation

identification capacity, Gaussian mean width, strong converse, quantum channels, semidefinite programming