[LR] Quixer: A Quantum Transformer Model
[This review is intended solely for my personal learning] [Qiix at Qiskit Hackathon Taiwan 2024 was inspired by this paper] Paper Info arXiv: 2406.04305 Title: Quixer: A Quantum Transformer Model Authors: Nikhil Khatri, Gabriel Matos, Luuk Coopmans, Stephen Clark (Quantinuum) Prior Knowledge Linear Combination of Unitaries (LCU) The LCU technique allows the combination of multiple unitary operators into one overall operator using additional control qubits and postselection. Given unitaries $U_0, U_1, \dots, U_{n-1}$ with complex coefficients $b_0, b_1, \dots, b_{n-1}$, one can effectively prepare a block-encoded operator $$ M = \sum_{j=0}^{n-1} b_j U_j. $$ ...