Parity-Based Time-Bin Encoding Enabling SWAP Between Polarization and Time-Bin Qubits
Abstract
Multi-degree-of-freedom photonic quantum processing requires routing between degree-of-freedom (DOF) qubit encodings on a single photon. A SWAP between polarization and time-bin qubits is an advantageous primitive for such architectures, however conventional early/late time-bin encoding does not support bidirectional logical time-bin flips from late to early which limits the ability to implement certain quantum operations. We introduce a parity-based time-bin encoding in which logical ket0T and ket1T correspond to even and odd multiples of a spacing Δt, so that a physical delay of Δt implements ket0T ↔ ket1T. This encoding is the enabling ingredient that makes a polarization-controlled delay line implement CNOTP → T and aligns naturally with periodic refractive index modulation for CNOTT → P. Composing three such CNOT operations sequentially results in a deterministic SWAP between polarization and time-bin degrees of freedom. We quantify how EOM voltage errors reduce the polarization-flip probability and estimate timing requirements from modulator switching, detector resolution, and timing jitter, giving an illustrative timing budget.
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BibTeX
@misc{sultan2026paritybased,
title = {{Parity-Based Time-Bin Encoding Enabling SWAP Between Polarization and Time-Bin Qubits}},
author = {Adam Sultan and Connor Kupchak},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.27144},
eprint = {2607.27144},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.27144},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Parity-Based Time-Bin Encoding Enabling SWAP Between Polarization and Time-Bin Qubits
AU - Adam Sultan
AU - Connor Kupchak
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2607.27144
UR - https://arxiv.org/abs/2607.27144
AB - Multi-degree-of-freedom photonic quantum processing requires routing between degree-of-freedom (DOF) qubit encodings on a single photon. A SWAP between polarization and time-bin qubits is an advantageous primitive for such architectures, however conventional early/late time-bin encoding does not support bidirectional logical time-bin flips from late to early which limits the ability to implement certain quantum operations. We introduce a parity-based time-bin encoding in which logical ket0_T and ket1_T correspond to even and odd multiples of a spacing Δt, so that a physical delay of Δt implements ket0_T ↔ ket1_T. This encoding is the enabling ingredient that makes a polarization-controlled delay line implement CNOT_P → T and aligns naturally with periodic refractive index modulation for CNOT_T → P. Composing three such CNOT operations sequentially results in a deterministic SWAP between polarization and time-bin degrees of freedom. We quantify how EOM voltage errors reduce the polarization-flip probability and estimate timing requirements from modulator switching, detector resolution, and timing jitter, giving an illustrative timing budget.
ER -