Fast Multiqubit Gates through Simultaneous Two-Qubit Gates
Artikel i vetenskaplig tidskrift, 2021
Near-term quantum computers are limited by the decoherence of qubits to only being able to run low-depth quantum circuits with acceptable fidelity. This severely restricts what quantum algorithms can be compiled and implemented on such devices. One way to overcome these limitations is to expand the available gate set from single- and two-qubit gates to multiqubit gates, which entangle three or more qubits in a single step. Here, we show that such multiqubit gates can be realized by the simultaneous application of multiple two-qubit gates to a group of qubits where at least one qubit is involved in two or more of the two-qubit gates. Multiqubit gates implemented in this way are as fast as, or sometimes even faster than, the constituent two-qubit gates. Furthermore, these multiqubit gates do not require any modification of the quantum processor, but are ready to be used in current quantum-computing platforms. We demonstrate this idea for two specific cases: simultaneous controlled-Z gates and simultaneous iswap gates. We show how the resulting multiqubit gates relate to other well-known multiqubit gates and demonstrate through numerical simulations that they would work well in available quantum hardware, reaching gate fidelities well above 99%. We also present schemes for using these simultaneous two-qubit gates to swiftly create large entangled states like Dicke and Greenberger-Horne-Zeilinger states.
Författare
Xiu Gu
Tencent
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
Jorge Fernández-Pendás
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
Pontus Vikstål
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
Tahereh Abad
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
Christopher Warren
Chalmers, Mikroteknologi och nanovetenskap, Kvantteknologi
Andreas Bengtsson
Chalmers, Mikroteknologi och nanovetenskap, Kvantteknologi
Giovanna Tancredi
Chalmers, Mikroteknologi och nanovetenskap, Kvantteknologi
Vitaly Shumeiko
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
Jonas Bylander
Chalmers, Mikroteknologi och nanovetenskap, Kvantteknologi
Göran Johansson
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
Anton Frisk Kockum
Chalmers, Mikroteknologi och nanovetenskap, Tillämpad kvantfysik
PRX Quantum
26913399 (eISSN)
Vol. 2 4 A202Ämneskategorier
Datorteknik
Annan elektroteknik och elektronik
Den kondenserade materiens fysik
DOI
10.1103/PRXQuantum.2.040348