Abstract: A quantum computing device including a doubly controlled iX (CCiX) circuit. The CCiX circuit may be configured to, in a preparation stage, prepare a plurality of magic states. The CCiX circuit may be further configured to receive a plurality of input qubit states including a first control qubit state, a second control qubit state, and a target qubit state. In an execution stage, the CCiX circuit may be further configured to perform a CCiX operation on the target qubit state at least in part by performing a plurality of local joint measurements. At least a subset of the plurality of local joint measurements may be performed between the plurality of magic states and a plurality of auxiliary qubits. Performing the CCiX operation may further include performing a plurality of remote joint measurements of the input qubit states and a plurality of interface qubits included among the plurality of auxiliary qubits.

Abstract: A quantum computing device is provided, including a table lookup circuit configured to receive a first table lookup input and a second table lookup input. The table lookup circuit may be further configured to perform a first table lookup operation on the first table lookup input and a second table lookup operation on the second table lookup input in parallel such that a combined table lookup output is written to a combined output register. The combined table lookup output may include a plurality of first table lookup output qubits of the first table lookup operation and a plurality of second table lookup output qubits of the second table lookup operation.

Abstract: This application concerns quantum computing devices and, more specifically, techniques for compiling a high-level description of a quantum program to be implemented in a quantum-computing device into a lower-level program that is executable by a quantum-computing device, where the high-level description of the quantum program to be implemented in a quantum-computing device supports at least one of loops and/or branches.

Abstract: A method for compiling executable code for execution on a computer includes: (a) receiving source code instructing the computer to execute an interval test to determine whether an interval defined by integers a and b encloses an integer x; (b) decomposing the interval test into a first comparison between the integer a and the integer x and a second comparison between the integer b and the integer x; and (c) returning instruction code directing the computer to evaluate the first and second comparisons cooperatively, at lower complexity than the combined complexities of the first and second comparisons enacted separately.

Abstract: A method for performing a quantum-logic operation on a quantum computer. The method includes enacting classical pebbling on an initial computation graph G defining the quantum-logic operation; extracting a quantum circuit B based on a sequence of steps obtained from the classical pebbling, that sequence including at least one computation step and at least one measurement-based uncomputation step; executing the quantum circuit B on a qubit register of the quantum computer; recording at least one measurement result of the at least one measurement-based uncomputation step of the quantum circuit B as executed on the qubit register; constructing a clean-up computation graph G? based on the at least one measurement result; enacting reversible pebbling on the clean-up computation graph G?; extracting a quantum circuit B? based on a sequence of steps obtained from the reversible pebbling, that sequence including computation and uncomputation steps; and executing the quantum circuit B? on the qubit register.

Abstract: This application concerns quantum computing devices. Certain embodiments comprise receiving a high-level description of a quantum program to be implemented in a quantum-computing device, and compiling the high-level description of the quantum program into a lower-level program that is executable by a quantum-computing device, wherein the high-level description of the quantum program to be implemented in a quantum-computing device supports at least one of loops and branches.