ColdQuanta, Inc.

A pulsed-laser applies short (e.g., less than 10 pico-seconds) pulses to modify quantum particle (e.g., alkali-metal and alkaline-earth-metal atoms) ultra-high vacuum (UHV) cells to bond, ablate, and/or chemically modify vacuum-facing surfaces of the cell. The pulses are generated outside the cell and are transmitted through a vacuum-boundary wall. In one example, one vacuum-boundary wall is first contact bonded to other vacuum boundary walls at a relatively low temperature (below 200° C.), sufficient to form a temporary hermetic seal. Pulsed laser bonding is used to reinforce the contact bonds, correcting defects and generally increasing the robustness of the seal. The pulses provide high peak power to ensure strong bonds, but low total heat so as to avoid heat damage to nearby cell components and to limit quantum-particle sorbtion to and into cell walls.

Each atom in a population of atoms can be characterized by a probability density distribution (PDD). Using a shaken-lattice technique, each PDD is split into a pair of sub-PDDs. The sub-PDDs of a pair are propagated along different paths to a common endpoint of the paths, resulting in a matter-wave interference pattern that encodes a net phase between the paths, e.g., due to differential effects associated with a gravity gradient. The matter-wave interference pattern can be measured to yield a respective measurement for each atom. The measurements can be aggregated to yield a result distribution that can serve as a classical domain estimate of the quantum-domain matter-wave interference pattern, and thus of the gravity gradient. Other embodiments can determine gradients for other types of fields.

Techniques are described for efficiently generating optical traps within a quantum information processor by resonantly enhancing optical trap light using an optical ring resonator. An optical ring resonator may effectively recycle optical trap light in a closed optical path, such that the optical trap light passes through a vacuum chamber many times, reinforcing the intensity of the optical traps. As such, a low power light source may be utilized to generate the optical traps. While such a light source may generate light with a power that is alone insufficient to produce the desired number of optical traps, the optical ring resonator reinforces the intensity of this light through repeated passes through the vacuum chamber, building up light of sufficient intensity to produce the desired number of optical traps in the vacuum chamber.

Techniques are described for efficient calibration of control parameters of a quantum information processor. The techniques include executing a quantum circuit a plurality of times while varying the value of a control parameter that parameterizes the quantum circuit. The quantum circuit may include quantum gates and/or other operations that are expected to produce a particular result when the control parameter is properly calibrated. By varying the value of the control parameter between successive executions of the quantum circuit, a calibrated value of the control parameter may be determined. Control parameters may, for instance, have values associated with a particular qubit, or with a particular pair (or larger group) of qubits.

A system including a magnetic coil and a coil driver is described. The magnetic coil has a parasitic capacitance. The coil driver is coupled with the magnetic coil. The coil driver includes a pulse generator and a switching module coupled with the pulse generator. The pulse generator provides a pulse train. The switching module receives the pulse train and provides a switched driving signal to the magnetic coil. The switched driving signal has a frequency not less than a parasitic capacitance frequency.

A quantum computer system uses a network of Mach-Zehnder interferometers (MZIs) to route laser light to selected atoms of a quantum array. The MZI network is defined in a photonic integrated circuit (PIC), which also includes an array of optical gratings. A laser system generates the light, the electronically controlled MZI network routes the light to respective optical gratings. The optical gratings convert the light from the MZI network into beams to illuminate the respective atoms so as to conditionally change their quantum states. This routing process offers advantages of economy, scalability and reliability over alternatives approaches to optical control of quantum states.

A system including a magnetic coil and a coil driver is described. The magnetic coil has a parasitic capacitance. The coil driver is coupled with the magnetic coil. The coil driver includes a pulse generator and a switching module coupled with the pulse generator. The pulse generator provides a pulse train. The switching module receives the pulse train and provides a switched driving signal to the magnetic coil. The switched driving signal has a frequency not less than a parasitic capacitance frequency.

A probe laser beam causes molecules to transition from a ground state to an excited state. A control laser beam causes molecules in the excited state to transition to a laser-induced Rydberg state. Microwave lenses convert a microwave wavefront into respective microwave beams. The microwave beams are counter-propagated through molecules so as to create a microwave interference pattern of alternating maxima and minima. The microwave interference pattern is imposed on the probe beam as a probe transmission pattern. The propagation direction of the microwave wavefront can be determined from the translational position of the probe transmission pattern; the intensity of the microwave wavefront can be determined by the intensity difference between the minima and maxima of the probe transmission pattern.

Techniques are described for deterministically returning Rydberg atoms from a Rydberg state to a ground state. These techniques allow for improved calibration of Rydberg excitations, and for detection of errors without the loss of atoms from traps described above. In particular, the techniques comprise applying a pulse to a Rydberg atom to transition the atom from a Rydberg state to a second state having a lower energy than the Rydberg state. These pulses, referred to here as “drain pulses,” are selected to produce the desired transition to the second state, referred to herein as a “drain state.” The drain state may be selected as a state that will decay, or which may be driven, to a ground state. Accordingly, the drain pulse provides a path for atoms to transition from a Rydberg state to a ground state.

A vacuum system is described. The vacuum system includes a vacuum cell and an ion trap. The vacuum cell includes walls having an inner surface that form at least a portion of a vacuum chamber. At least a portion of the inner surface has a topography including structures therein. The structures include a getter material. The ion trap is within the vacuum chamber.