Related Experiment Video
Updated: Aug 16, 2025

Plasmid-derived DNA Strand Displacement Gates for Implementing Chemical Reaction Networks
Published on: November 25, 2015
Constant-Cost Implementations of Clifford Operations and Multiply-Controlled Gates Using Global Interactions
Sergey Bravyi1, Dmitri Maslov1, Yunseong Nam2
1IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Abstract:
We consider quantum circuits composed of single-qubit operations and global entangling gates generated by Ising-type Hamiltonians. It is shown that such circuits can implement a large class of unitary operators commonly used in quantum algorithms at a very low cost-using a constant or effectively constant number of global entangling gates. Specifically, we report constant-cost implementations of Clifford operations with and without ancillae, constant-cost implementation of the multiply-controlled gates with linearly many ancillae, and an O(log^{*}(n)) cost implementation of the n-controlled single-target gates using logarithmically many ancillae. This shows a significant asymptotic advantage of circuits enabled by the global entangling gates.
Related Concept Videos
Design Example: Forces in Sluice Gate
Key variables in...
Clamper Circuit
Within this circuit, the diode's orientation prompts the capacitor to charge up to the level of the most negative peak of the input signal. Upon reaching this state, the diode ceases to...
Current Growth And Decay In RL Circuits
Second-Order Circuits
Input signals typically originate from voltage or current sources, with the output often representing voltage across the capacitor and/or current through the inductor. For example, in...
Underflow Gates
Design Example: Capacitance Multiplier Circuit
The circuit illustrated in Figure 1 below incorporates two op-amps, with the first operating as a voltage follower and the second acting as an inverting amplifier.

