IQM FINLAND OY

It is an objective to provide an arrangement for resetting at least one qubit. According to an embodiment, an arrangement for resetting at least one qubit comprises at least one qubit; an energy dissipation structure selectively couplable to the at least one qubit; and a control unit, configured to reset the at least one qubit by performing: couple the at least one qubit to the energy dissipation structure for a reset period using a control signal, wherein the control signal controls a coupling strength between the at least one qubit and the energy dissipation structure; and after the reset period, decouple the at least one qubit from the energy dissipation structure during a decoupling period using the control signal, wherein the coupling strength comprises, during the decoupling period, at least a temporally linearly decreasing component and at least one temporally sinusoidal component.

An apparatus and a method for facilitating a first frequency filtering and a second frequency filtering together with non-reciprocal frequency conversion for electromagnetic isolation.

Various example embodiments relate to an arrangement for resetting at least one qubit. According to an embodiment, the arrangement comprises the at least one qubit, a dissipative environment, and a control unit configured to reset the at least one qubit by performing operations comprising applying a reset signal to the qubit. The reset signal is generated by amplitude modulation. The reset signal induces at least one sideband mode of the qubit. The sideband mode of the qubit overlaps with a frequency of the dissipative environment.

Provided is a computer-implemented method of compiling at least a part of a quantum circuit comprising gates to be performed on logical qubits to a quantum processing unit architecture having physical qubits with restricted hardware connectivity, the method comprising: identifying a mapping between the logical qubits and the physical qubits and compiling an initial subset of the gates of the quantum circuit; and identifying a routing of at least the part of the quantum circuit that iteratively incorporates SWAP gates reducing a distance between an iteration subset of the gates. Provided is also a quantum compiler configured to implement the above method as well as a quantum computer having a quantum processing unit architecture having physical qubits with restricted hardware connectivity, the quantum computer configured to execute a quantum circuit compiled according to the above method.

Example embodiments relate to delivery of qubit drive signals to a cryogenic environment of a quantum computer. Qubit drive signal(s) may be conveyed to the cryogenic environment as optical signal(s). The optical signal(s) may be transduced to radio frequency signal(s) at the cryogenic environment for driving qubit(s). Apparatuses and methods are disclosed.

A quantum information processing system may comprise a quantum mechanical system capable of exhibiting transitions between a plurality of eigenstates; and a quantum control environment, wherein the quantum control environment eigenstates is capable of exhibiting modes from a continuous spectrum and is coupled to the quantum mechanical system at at least one coupling location, wherein said coupling is characterized with a set of parameters of the quantum mechanical system, and wherein a selected combination of the at least one coupling location and the set of parameters intentionally causes to suppress at least one of said transitions when intentionally changing a state of the quantum mechanical system by the quantum control environment.

A tunable coupler for making a controllable coupling to at least a first qubit is disclosed. The tunable coupler includes a first constant coupling element and a tunable coupling element. The first constant coupling element forms a non-galvanic coupling interface to at least the first qubit at a first extremity that is distant from the tunable coupling element. The tunable coupling element is located adjacent to a non-galvanic coupling interface formed as an interface to a circuit element at a second extremity thereof.

This disclosure describes a quantum computing circuit comprising a set of qubits. The circuit comprises drivelines for addressing the qubits. The drivelines comprise one or more x-drivelines and one or more y-drivelines which form a grid. The quantum computing circuit comprises a set of bandpass filters, coupled between the drivelines and the set of qubits so that each qubit is coupled to one x-driveline and to one y-driveline with a bandpass filter.

An AQFP circuit comprises a Josephson junction having a respective plasma frequency, a clocking signal line, an inductive coupler between said clocking signal line and said Josephson junction, and a data signal line be-tween a data signal source and said Josephson junction. The AQFP circuit is configured to feed into said clocking signal line an oscillating clocking signal having a clocking signal frequency selected so that said plasma frequency is an integral multiple of said clocking signal frequency.

Disclosed is an apparatus and a method for facilitating a first frequency filtering and a second frequency filtering together with non-reciprocal frequency conversion for electromagnetic isolation.