IonQ Inc

As used in this Annual Report on Form 10-K, unless the context otherwise requires, references to the following terms have the respective meaning as defined below:

Algorithmic Qubit: A metric describing the number of “useful” qubits in a system, considering noise, connectivity limitations, and other sources of error.

Barium: A silvery rare-earth metal, atomic number 56, that can be used as a qubit for quantum computing. IonQ has recently started exploring barium as an alternative qubit species because its slightly more complex structure offers higher fundamental gate and readout fidelities when controlled correctly, and because it primarily interacts with light in the visible spectrum, allowing additional opportunities for standard fiber optic technologies in parts of the system.

Classical Computer: A computer that stores and calculates information using classical mechanics: information is stored as a 0 or a 1, in a transistor.

Coherence Time: A measurement of the “lifetime” of a qubit, coherence time measures how long a qubit can maintain coherent phase, which allows it to successfully retain quantum information and behave in the ways necessary for it to be part of a useful computation.

Entanglement: A property of quantum mechanics where two particles, even when physically separated, behave in ways conditionally dependent on each other.

Error-Corrected Qubit: Groups of physical qubits that are logically combined using techniques called error correction encoding with the goal of having them act together as one much higher-quality qubit for computational purposes.

Fault Tolerance: A system’s ability to accommodate errors in its operation without losing the information it is processing and/or storing.

Gate Fidelity/Error Rate: A measure of how much noise (or error) is introduced in each operation during a quantum algorithm.

Ion Trap: An apparatus that holds ions in place, ready for computation, in a trapped-ion quantum computer.

Measurement: The process at the end of a quantum computation where the exponentially large computational space available during computation collapses down to a binary string in order to produce readable results.

Multi-Core QPU: A single quantum processor that has multiple quantum compute zones that can compute in parallel and be entangled via moving and recombining ion chains.

Noise: For quantum computers to compute correctly, they must be isolated from the environment around them. Any interaction with the environment, or imperfection in the control systems that perform gates, introduces noise. As noise accumulates, the overall likelihood that an algorithm will produce a successful answer goes down. With too much noise, a quantum computer is no longer useful at all.

Photonic Interconnect: A connection between two qubits using photons, typically via a fiber optic cable. A photonic interconnect is used to remotely connect two qubits.

Physical Qubit: The hardware implementation of a qubit in a quantum computer.

Quantum Algorithm: A series of quantum logic gates that together solve a specific problem.

Quantum Bit (Qubit): The quantum equivalent of bits in classical computing, able to exist in a superposition of states and be entangled with other qubits.

Quantum Circuit: A collection of quantum logic gates to be run in a specific order on a given set of qubits.

Quantum Logic Gate(s): Gates used to manipulate the state of qubits, including putting them in superposition states and creating entanglement.

Quantum Processing Unit (QPU): A complete system made up of physical qubits and the apparatus for controlling them.

Superconducting Qubit: A qubit implementation that uses specialized silicon-fabricated chips at ultracold temperatures.

Synthetic (Fabricated) Qubit: A qubit that uses an engineered or “manufactured” quantum system, rather than a naturally occurring one. Examples of synthetic (fabricated) qubits include superconducting transmon qubits and semiconductor quantum dot qubits.

Trapped Ion Qubit: A qubit implementation using charged atomic particles (ions) suspended in vacuum and manipulated with lasers.

Part I