How fast can one route quantum states


Yin, C. (2024). How fast can one route quantum states. Perimeter Institute. https://pirsa.org/24030122


Yin, Chao. How fast can one route quantum states. Perimeter Institute, Mar. 20, 2024, https://pirsa.org/24030122


          @misc{ pirsa_PIRSA:24030122,
            doi = {10.48660/24030122},
            url = {https://pirsa.org/24030122},
            author = {Yin, Chao},
            keywords = {Quantum Information},
            language = {en},
            title = {How fast can one route quantum states},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {mar},
            note = {PIRSA:24030122 see, \url{https://pirsa.org}}

Chao Yin University of Colorado Boulder


Many quantum platforms naturally host Hamiltonians with power-law or even all-to-all connectivity, which may potentially process quantum information in a way much faster than conventional gate-based models. For such non-geometrically-local Hamiltonians, it is then important to both come up with fast protocols and understand the ultimate limit for realizing various information processing tasks. In this talk, I will first overview this quantum speed limit topic, and then dive into the particular task of quantum routing, i.e. permuting unknown quantum states on the qubits. I aim to show [1] a provably optimal Hamiltonian routing protocol on the star graph that is asymptotically faster than gate-based routing; [2] a lower bound on the time to realize the shift unitary using 1d power-law interactions which, perhaps surprisingly, can be much slower than the time for the conventional Lieb-Robinson light cone to spread across the whole system. The latter result shares interesting connections to the classification of 1d quantum cellular automata and symmetry-protected topological order.


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