Abstract: A method includes providing a first quantum state at a first node, transforming the first quantum state to obtain a first plurality of transformed quantum states, and measuring the first plurality of transformed quantum states to obtain a first set of measurement results. The method further includes providing a second quantum state at a second node, transforming the second quantum state to obtain a second plurality of transformed quantum states, the second plurality of unitary operations corresponding to the first plurality of unitary operations, and measuring the second plurality of transformed quantum states to obtain a second set of measurement results. A similarity measure between the first quantum state and the second quantum state is determined in terms of the first set of measurement results and the second set of measurement results, the similarity measure including a trace product of the first quantum state and the second quantum state.

Abstract: The present disclosure provides electrode portions for generating electric and/or magnetic fields for trapping ions in a trapping zone, a three-dimensional (3D) ion trap including one or more of such electrode portions, systems for trapping ions with such a 3D ion trap, as well as methods for manufacturing such electrode portions. An electrode portions includes an electrode body made of an electrically insulating substrate and elongated in a first direction towards the ion trapping zone, a peak electrode located on an extremity of the electrode body closest to the trapping zone or a side electrode located laterally relative to the extremity, and a connection connected to the peak electrode and leading from the peak electrode through said electrode body away from the trapping zone.

Abstract: Provided is a method of reducing the magnitude of a quasi-static electric dipole field at the null position of an oscillating electric quadrupole field of an ion trap. The method includes trapping at least one ion in a trapping electric field. The trapping electric field includes an electric field amplitude; using an interferometry sequence including applying a first laser pulse when the trapping electric field amplitude includes a first trapping electric field amplitude; applying a second laser pulse when the trapping electric field amplitude includes a second trapping electric field amplitude different from the first electric field amplitude; and measuring a state of the ion; repeating the interferometry sequence in order to obtain a plurality of measurements of the state of the ion; determining a probability that the trapped ion changes state; and adjusting the trapping electric field based on the determined probability.

Abstract: Some embodiments in the present disclosure relate to an apparatus and methods to excite a trapped ion. A first laser beam and a second laser beam pass through at least one common lens of an objective. The two laser beams are focused by said objective at the position of the trapped ion. A moving standing wave is generated at the position of the trapped ion, which induces a force on the trapped ion. Two ions may be entangled by generating such moving standing wave at the respective positions of both of said ions.

Abstract: A method of measuring a physical quantity implemented in a hybrid classical-quantum system, the method comprising initializing the plurality of controllable quantum systems in an initial state, applying a set of preparation gates to the plurality of controllable quantum systems for preparing the plurality of controllable quantum systems in a non-classical state, evolving the non-classical state over a time period for obtaining an evolved state of the plurality of controllable quantum systems, applying a set of decoding gates to the plurality of controllable quantum systems in the evolved state, performing a measurement of the plurality of controllable quantum systems, and determining a derived value of the physical quantity based on a mapping function between an outcome of the measurement and the physical quantity on the classical computation system.

Abstract: An ion trap device is disclosed with a method of manufacturing thereof including a substrate, first and second RF electrode rails, first and second DC electrodes on either upper or lower side of substrate, and a laser penetration passage connected to ion trapping zone from outer side of the first or second side of substrate. The substrate includes ion trapping zone in space defined by first and second sides of substrate separated by a distance with reference to width direction of ion trap device. The first and second RF electrode rails are arranged in parallel longitudinally of ion trap device. The first RF electrode is arranged on upper side of first side, the second DC electrode is arranged on lower side of first side, the first DC electrode is arranged on upper side of second side, and the second RF electrode rail is arranged on lower side of second side.