Flagged Extensions and Numerical Simulations for Quantum Channel Capacity: Bridging Theory and Computation

• URL: http://arxiv.org/abs/2506.03429v1
• Date: Tue, 03 Jun 2025 22:21:08 GMT
• Title: Flagged Extensions and Numerical Simulations for Quantum Channel Capacity: Bridging Theory and Computation
• Authors: Vahid Nourozi,
• Abstract summary: I will investigate the capacities of noisy quantum channels through a combined analytical and numerical approach.<n>I introduce novel flagged extension techniques that embed a channel into a higher-dimensional space.<n>My results refine previous bounds and clarify noise thresholds beyond which quantum transmission vanishes.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: I will investigate the capacities of noisy quantum channels through a combined analytical and numerical approach. First, I introduce novel flagged extension techniques that embed a channel into a higher-dimensional space, enabling single-letter upper bounds on quantum and private capacities. My results refine previous bounds and clarify noise thresholds beyond which quantum transmission vanishes. Second, I present a simulation framework that uses coherent information to estimate channel capacities in practice, focusing on two canonical examples: the amplitude damping channel (which we confirm is degradable and thus single-letter) and the depolarizing channel (whose capacity requires multi-letter superadditivity). By parameterizing input qubit states on the Bloch sphere, I numerically pinpoint the maximum coherent information for each channel and validate the flagged extension bounds. Notably, I capture the abrupt transition to zero capacity at high noise and observe superadditivity for moderate noise levels.

Related papers

• Crosstalk-Resilient Quantum MIMO for Scalable Quantum Communications [40.44880302154388]
  Crosstalk arises when physically coupled quantum modes interfere, degrading signal fidelity.<n>We propose a mitigation strategy based on encoding discrete-variable quantum information into continuous-variable modes.<n>We prove the existence of a gauge-fixing decoder enabling recovery of the logical information.
  arXiv  Detail & Related papers  (2025-06-26T18:40:26Z)
• Optimizing entanglement distribution via noisy quantum channels [44.99833362998488]
  Entanglement distribution is a crucial problem in quantum information science.<n>We investigate strategies for distributing quantum entanglement between two distant parties through noisy quantum channels.
  arXiv  Detail & Related papers  (2025-06-06T13:48:20Z)
• The multimode conditional quantum Entropy Power Inequality and the squashed entanglement of the extreme multimode bosonic Gaussian channels [53.253900735220796]
  Inequality determines the minimum conditional von Neumann entropy of the output of the most general linear mixing of bosonic quantum modes. Bosonic quantum systems constitute the mathematical model for the electromagnetic radiation in the quantum regime.
  arXiv  Detail & Related papers  (2024-10-18T13:59:50Z)
• Unextendible entanglement of quantum channels [4.079147243688764]
  We study the ability of quantum channels to perform quantum communication tasks. A quantum channel can distill a highly entangled state between two parties. We generalize the formalism of $k$-extendibility to bipartite superchannels.
  arXiv  Detail & Related papers  (2024-07-22T18:00:17Z)
• Accurate and Honest Approximation of Correlated Qubit Noise [39.58317527488534]
  We propose an efficient systematic construction of approximate noise channels, where their accuracy can be enhanced by incorporating noise components with higher qubit-qubit correlation degree.<n>We find that, for realistic noise strength typical for fixed-frequency superconducting qubits, correlated noise beyond two-qubit correlation can significantly affect the code simulation accuracy.
  arXiv  Detail & Related papers  (2023-11-15T19:00:34Z)
• Information capacity analysis of fully correlated multi-level amplitude damping channels [0.9790236766474201]
  We investigate some of the information capacities of the simplest member of multi-level Amplitude Damping Channel, a qutrit channel. We find the upper bounds of the single-shot classical capacities and calculate the quantum capacities associated with a specific class of maps.
  arXiv  Detail & Related papers  (2023-05-08T06:10:56Z)
• Fault-tolerant Coding for Entanglement-Assisted Communication [46.0607942851373]
  This paper studies the study of fault-tolerant channel coding for quantum channels. We use techniques from fault-tolerant quantum computing to establish coding theorems for sending classical and quantum information in this scenario. We extend these methods to the case of entanglement-assisted communication, in particular proving that the fault-tolerant capacity approaches the usual capacity when the gate error approaches zero.
  arXiv  Detail & Related papers  (2022-10-06T14:09:16Z)
• Suppressing Amplitude Damping in Trapped Ions: Discrete Weak Measurements for a Non-unitary Probabilistic Noise Filter [62.997667081978825]
  We introduce a low-overhead protocol to reverse this degradation. We present two trapped-ion schemes for the implementation of a non-unitary probabilistic filter against amplitude damping noise. This filter can be understood as a protocol for single-copy quasi-distillation.
  arXiv  Detail & Related papers  (2022-09-06T18:18:41Z)
• Exact solution for the quantum and private capacities of bosonic dephasing channels [10.787390511207686]
  We provide the first exact calculation of the quantum, private, two-way assisted quantum, and secret-key capacities of bosonic dephasing channels.
  arXiv  Detail & Related papers  (2022-05-11T19:12:12Z)
• Entanglement catalysis for quantum states and noisy channels [41.94295877935867]
  We investigate properties of entanglement and its role for quantum communication. For transformations between bipartite pure states, we prove the existence of a universal catalyst. We further develop methods to estimate the number of singlets which can be established via a noisy quantum channel.
  arXiv  Detail & Related papers  (2022-02-10T18:36:25Z)
• Energy-constrained LOCC-assisted quantum capacity of bosonic dephasing channel [0.0]
  We study the LOCC-assisted quantum capacity of bosonic dephasing channel with energy constraint on input states. We derive explicit upper and lower bounds for the energy-constrained LOCC-assisted quantum capacity of the bosonic dephasing channel.
  arXiv  Detail & Related papers  (2021-11-07T20:21:33Z)
• Experimental Lower Bounds to the Classical Capacity of Quantum Channels [0.0]
  We show an experimental procedure to certify the classical capacity for noisy qubit channels. The method makes use of a fixed bipartite entangled state, where the system qubit is sent to the channel input.
  arXiv  Detail & Related papers  (2020-11-17T16:24:09Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.