@misc{10481/110641, year = {2025}, month = {12}, url = {https://hdl.handle.net/10481/110641}, abstract = {Transversal encoded gatesets are highly desirable for fault tolerant quantum computing. However, a quantum error correcting code which exactly corrects for local erasure noise and supports a universal set of transversal gates is ruled out by the Eastin-Knill theorem. Here, we provide a new approximate Eastin-Knill theorem for the single-shot regime when we allow for some probability of error in the decoding. In particular, we show that a quantum error correcting code can support a universal set of transversal gates and approximately correct for local erasure if and only if the conditional min-entropy of the Choi state of the encoding and noise channel is upper bounded by a simple function of the worstcase error probability. Our no-go theorem can be computed by solving a semidefinite program, and, in the spirit of the original Eastin-Knill theorem, is formulated in terms of a condition that is both necessary and sufficient, ensuring achievability whenever it is passed. As an example, we find that with n = 100 physical qutrits we can encode k = 1 logical qubit in the W-state code, which admits a universal transversal set of gates and corrects for single subsystem erasure with error probability of ε = 0.005. To establish our no-go result, we leverage tools from the resource theory of asymmetry, where, in the single-shot regime, a single (output state-dependent) resource monotone governs all state purifications.}, organization = {Ministry for Digital Transformation and of Civil Service of the Spanish Government through projects, PID2024-162155OB-I00, PID2021-128970OA-I00 10.13039/501100011033 and QUANTUM ENIA project call - Quantum Spain project}, organization = {European Union through the Recovery, Transformation and Resilience Plan - NextGenerationEU within the framework of the Digital Spain 2026 Agenda}, organization = {EU HORIZON RIA FoQaCiA GA 101070558}, publisher = {Springer Nature}, title = {A new approximate Eastin-Knill theorem}, doi = {10.1038/s41534-025-01156-0}, author = {Alexander-Turner, Rhea}, }