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| Autore principale: | |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| Accesso online: | https://arxiv.org/abs/2605.19248 |
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| _version_ | 1866910234944995328 |
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| author | Dubey, Sagar |
| author_facet | Dubey, Sagar |
| contents | We consider $(n,k)$ MDS-coded distributed storage over $\mathbb{F}_q$ with per-node storage $α$ symbols. For the oblivious update problem, where a single message symbol changes and neither helpers nor the stale node know which, the classical lower bound is $αk \log_2 q$ bits. We prove that when the $k$ contacted helpers share prior quantum entanglement, the update bandwidth is $\lceil α/2 \rceil \cdot k \log_2 q$ bits-equivalent, a factor approaching 2 reduction. For $α= 2$, a $[[k, k-2]]_q$ CSS code achieves bandwidth $k \log_2 q$ with one qudit per helper. For general $α$, a $[[\lceil α/2 \rceil k, \lceil α/2 \rceil k - α]]_q$ CSS code achieves the bound with $\lceil α/2 \rceil$ qudits per helper. The matching converse uses the superdense coding bound: the stale node holds all transmitted qudits and hence the entangled partners, so each helper's channel supports at most $D^2$ distinguishable signals for dimension $D$. The result holds for all $(n,k)$ pairs with sufficiently large prime $q$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_19248 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Quantum Entanglement Halves the Oblivious Update Bandwidth Dubey, Sagar Quantum Physics Information Theory We consider $(n,k)$ MDS-coded distributed storage over $\mathbb{F}_q$ with per-node storage $α$ symbols. For the oblivious update problem, where a single message symbol changes and neither helpers nor the stale node know which, the classical lower bound is $αk \log_2 q$ bits. We prove that when the $k$ contacted helpers share prior quantum entanglement, the update bandwidth is $\lceil α/2 \rceil \cdot k \log_2 q$ bits-equivalent, a factor approaching 2 reduction. For $α= 2$, a $[[k, k-2]]_q$ CSS code achieves bandwidth $k \log_2 q$ with one qudit per helper. For general $α$, a $[[\lceil α/2 \rceil k, \lceil α/2 \rceil k - α]]_q$ CSS code achieves the bound with $\lceil α/2 \rceil$ qudits per helper. The matching converse uses the superdense coding bound: the stale node holds all transmitted qudits and hence the entangled partners, so each helper's channel supports at most $D^2$ distinguishable signals for dimension $D$. The result holds for all $(n,k)$ pairs with sufficiently large prime $q$. |
| title | Quantum Entanglement Halves the Oblivious Update Bandwidth |
| topic | Quantum Physics Information Theory |
| url | https://arxiv.org/abs/2605.19248 |