



01276nas a2200157   4500008004100000245007700041210006900118260001300187520076900200100002200969700002400991700001901015700002201034700002501056856003701081       2020                        eng d00aAsymmetric blockade and multi-qubit gates via dipole-dipole interactions0 aAsymmetric blockade and multiqubit gates via dipoledipole intera  c6/3/20203 a<p>Due to their strong and tunable interactions, Rydberg atoms can be used to realize fast two-qubit entangling gates. We propose a generalization of a generic two-qubit Rydberg-blockade gate to multi-qubit Rydberg-blockade gates which involve both many control qubits and many target qubits simultaneously. This is achieved by using strong microwave fields to dress nearby Rydberg states, leading to asymmetric blockade in which control-target interactions are much stronger than control-control and target-target interactions. The implementation of these multi-qubit gates can drastically simplify both quantum algorithms and state preparation. To illustrate this, we show that a 25-atom GHZ state can be created using only three gates with an error of 7.8%.</p>1 aYoung, Jeremy, T.1 aBienias, Przemyslaw1 aBelyansky, Ron1 aKaufman, Adam, M.1 aGorshkov, Alexey, V.  uhttps://arxiv.org/abs/2006.0248601475nas a2200181   4500008004100000245010000041210006900141260001400210520088000224100001901104700002201123700002401145700002201169700002201191700001801213700002501231856003701256       2019                        eng d00aNondestructive cooling of an atomic quantum register via state-insensitive Rydberg interactions0 aNondestructive cooling of an atomic quantum register via statein  c7/28/20193 a<p>We propose a protocol for sympathetically cooling neutral atoms without destroying the quantum information stored in their internal states. This is achieved by designing state-insensitive Rydberg interactions between the data-carrying atoms and cold auxiliary atoms. The resulting interactions give rise to an effective phonon coupling, which leads to the transfer of heat from the data atoms to the auxiliary atoms, where the latter can be cooled by conventional methods. This can be used to extend the lifetime of quantum storage based on neutral atoms and can have applications for long quantum computations. The protocol can also be modified to realize state-insensitive interactions between the data and the auxiliary atoms but tunable and non-trivial interactions among the data atoms, allowing one to simultaneously cool and simulate a quantum spin-model.&nbsp;</p>1 aBelyansky, Ron1 aYoung, Jeremy, T.1 aBienias, Przemyslaw1 aEldredge, Zachary1 aKaufman, Adam, M.1 aZoller, Peter1 aGorshkov, Alexey, V.  uhttps://arxiv.org/abs/1907.11156