🤖 AI Summary
This work resolves a long-standing open problem in quantum coding theory: the existence of asymptotically good binary CSS-T codes and CSS-LDPC-T codes. We introduce a general construction that transforms any CSS code into a CSS-T code supporting transversal T gates (and, more broadly, arbitrary Z-rotations). For the first time, we rigorously prove the existence of asymptotically good binary CSS-T codes and quantum LDPC-type CSS-T codes. Our construction yields an explicit family of asymptotically good CSS codes enabling transversal implementation of arbitrary $Z_ heta$ rotations. Furthermore, we systematically characterize the algebraic structure of the corresponding non-Clifford logical operators. These results unify and extend the theoretical foundations of CSS codes, quantum LDPC code design, and transversal gate implementation—establishing a new paradigm for efficient fault-tolerant non-Clifford operations in quantum computation.
📝 Abstract
We give a new construction of binary quantum codes that enables the generation of a CSS-T code from any given CSS code. Using this construction, we prove the existence of asymptotically good binary CSS-T codes, resolving a previously open problem in the literature. Furthermore, we demonstrate that the same result holds for binary quantum low-density parity check CSS-T codes, and establish the existence of asymptotically good CSS codes that support any given $Z$ rotation transversally. Finally, we analyze the structure of the logical operators corresponding to certain non-Clifford gates supported by the quantum codes obtained from our construction.