5 papers · 1 filter
Simulating the quantum switch with quantum circuits is computationally hard
Jessica Bavaresco, Hlér Kristjánsson, Mio Murao +4
Higher-order transformations acting on input quantum channels in an indefinite causal order, such as the quantum switch, cannot be described by quantum circuits using the same numb…
Consistent circuits for indefinite causal order
Augustin Vanrietvelde, Nick Ormrod, Hlér Kristjánsson +1
Over the past decade, a number of quantum processes have been proposed which are logically consistent, yet feature a cyclic causal structure. However, there is no general formal me…
Universal algorithm for transforming Hamiltonian eigenvalues
Tatsuki Odake, Hlér Kristjánsson, Philip Taranto +1
Manipulating Hamiltonians governing physical systems has found a broad range of applications, from quantum chemistry to semiconductor design. In this work, we provide a new way of…
Exponential separation in quantum query complexity of the quantum switch with respect to simulations with standard quantum circuits
Hlér Kristjánsson, Tatsuki Odake, Satoshi Yoshida +4
Quantum theory is consistent with a computational model permitting black-box operations to be applied in an indefinite causal order, going beyond the standard circuit model of comp…
Quantum gravity as a communication resource
Richard Howl, Ali Akil, Hlér Kristjánsson +2
Quantum information can provide a lens for characterizing the operational implications of spacetime physics. A well-known result in this area is that quantum entanglement is degrad…