We report on a new computer study of the existence of d2 equiangular lines in d complex dimensions. Such maximal complex projective codes are conjectured to exist in all finite dimensions and are the underlying mathematical objects defining symmetric informationally complete measurements in quantum theory. We provide numerical solutions in all dimensions d≤67 and, moreover, a putatively complete list of Weyl–Heisenberg covariant solutions for d≤50. A symmetry analysis of this list leads to new algebraic solutions in dimensions d=24, 35, and 48, which are given together with algebraic solutions for d=4,…,15, and 19.

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The quantum erasure channel (QEC) is considered. Codes for the QEC have to correct for erasures, i. e., arbitrary errors at known positions. We show that four qubits are necessary and sufficient to encode one qubit and correct one erasure, in contrast to five qubits for unknown positions. Moreover, a family of quantum codes for the QEC, the quantum BCH codes, that can be efficiently decoded is introduced.