2016/11/12 by Yuichiro Matsuzaki, Shojun Nakayama, Akihito Soeda +2
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Classical mechanics #Combinatorics #Computer science #Dimension (graph theory) #Eigenvalues and eigenvectors #Energy (signal processing) #Hamiltonian (control theory) #Hamiltonian system #Mathematical optimization #Mathematics #Mechanical and Optical Resonators #Physics #Projection (relational algebra) #Projective test #Pure mathematics #Quantum #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum mechanics #Qubit #Topology (electrical circuits) #quant-ph
paper · pdf · doi:10.1103/physreva.95.062106
published as Phys. Rev. A 95, 062106 (2017)
arxiv created 2016/11/12 · openalex created_date 2016/11/30 · openalex publication_date 2017/06/08 · arxiv updated 2017/06/14 · openalex updated_date 2026/08/05
In projective measurements of energy, a target system is projected to an eigenstate of the system Hamiltonian and the measurement outcomes provide the information of corresponding eigenenergies. Recently, it has been shown that such a measurement can be, in principle, realized without detailed knowledge of the Hamiltonian by using probe qubits. However, in this approach, the size of the dimension for the probe increases as we increase the dimension of the target system; also, individual addressability of every qubit is required, which may not be possible for many experimental settings involving large systems. Here, we show that a single probe qubit is sufficient to perform such a projective measurement of energy if the target system is composed of noninteracting qubits whose resonant frequencies are unknown. Moreover, our scheme requires only global manipulations where every qubit is subjected to the same control fields. These results indicate the feasibility of our energy-projection protocols.