2025/11/07 by Hayden Zammit, Roberto Salazar, Zammit, Hayden +7
Computer Science · Physics and Astronomy · #Amplitude damping channel #Formalism (music) #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum capacity #Quantum channel #Quantum discord #Quantum information #Quantum key distribution #Quantum network #Quantum operation #Quantum optics and atomic interactions
paper · pdf · doi:10.1088/1751-8121/ae85ea
published in Journal of Physics A Mathematical and Theoretical 59(29), 295305 (Institute of Physics)
openalex publication_date 2026/07/02 · openalex created_date 2026/07/03 · openalex updated_date 2026/07/25
Abstract Quantum information processing (QIP) tasks can be efficiently formulated in terms of quantum dynamical maps, whose formalism is able to provide the appropriate mathematical representation of the evolution of open quantum systems. A key QIP task is quantum state transfer (QST) aimed at sharing quantum information between distant nodes of a quantum network, enabling, for example, quantum key distribution and distributed quantum computing. QST has thus far primarily been addressed by resetting the quantum channel after each use, thereby giving rise to memoryless channels. Here we consider the case where the quantum channel, embodied by a spin- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mfrac> <mml:mn>1</mml:mn> <mml:mn>2</mml:mn> </mml:mfrac> </mml:mrow> </mml:math> chain, is continuously used, that is, without implementing time- and resource-consuming resetting operations. We derive a general, analytical expression for the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>n</mml:mi> <mml:mrow> <mml:mrow> <mml:mi>th</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> -use average QST fidelity for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>U</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mn>1</mml:mn> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> -symmetric channels and apply our formalism to a perfect QST channel in the presence of imperfect readout timing. We show that even relatively small readout timing errors give rise to memory effects which have a highly detrimental impact on subsequent QST tasks.