Experimental comparison of two quantum computing architectures.
We run a selection of algorithms on two state-of-the-art 5-qubit quantum computers that are based on different technology platforms. One is a publicly accessible superconducting transmon device (www.



ibm.com/ibm-q) with limited connectivity, and the other is a fully connected trapped-ion system. Even though the two systems have different native quantum interactions, both can be programed in a way that is blind to the underlying hardware, thus allowing a comparison of identical quantum algorithms between different physical systems. We show that quantum algorithms and circuits that use more connectivity clearly benefit from a better-connected system of qubits. Although the quantum systems here are not yet large enough to eclipse classical computers, this experiment exposes critical factors of scaling quantum computers, such as qubit connectivity and gate expressivity. In addition, the results suggest that codesigning particular quantum applications with the hardware itself will be paramount in successfully using quantum computers in the future.
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742; monroe@umd.edu linke@umd.edu.|Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742.
Norbert M
NM
Linke
National Science Foundation, Arlington, VA 22230.
Dmitri
D
Maslov
Microsoft Research, Redmond, WA 98052.
Martin
M
Roetteler
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742.|Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742.
Shantanu
S
Debnath
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742.|Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742.
Caroline
C
Figgatt
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742.|Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742.
Kevin A
KA
Landsman
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742.|Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742.
Kenneth
K
Wright
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742; monroe@umd.edu linke@umd.edu.|Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742.|IonQ Inc., College Park, MD 20742.
Christopher
C
Monroe
quantum computing; quantum computing architecture; quantum information; quantum information science; quantum physics