Realization of efficient quantum gates with a superconducting qubit-qutrit circuit

Abstract

Building a quantum computer is a daunting challenge since it requires good control but also good isolation from the environment to minimize decoherence. It is therefore important to realize quantum gates efficiently, using as few operations as possible, to reduce the amount of required control and operation time and thus improve the quantum state coherence. Here we propose a superconducting circuit for implementing a tunable system consisting of a qutrit coupled to two qubits. This system can efficiently accomplish various quantum information tasks, including generation of entanglement of the two qubits and conditional three-qubit quantum gates, such as the Toffoli and Fredkin gates. Furthermore, the system realizes a conditional geometric gate which may be used for holonomic (non-adiabatic) quantum computing. The efficiency, robustness and universality of the presented circuit makes it a promising candidate to serve as a building block for larger networks capable of performing involved quantum computational tasks.

Reducing the Amount of Single‐Qubit Rotations in VQE and Related Algorithms

“…Due to the fact that the Fredkin gate itself is difficult to implement, we consider instead a multiple controlled i swap gate, as it occurs naturally in many solid state system used to implement quantum information schemes. [ 49–51 ]…”

“…Due to the fact that the Fredkin gate itself is difficult to implement, we consider instead a multiple controlled iswap gate, as it occurs naturally in many solid state system used to implement quantum information schemes. [49][50][51] We consider the n-bit iswap gate, the n-bit Toffoli, and the nbit iToffoli as the V gate one at a time. The result using these gates can be seen in Figure 3c, Figure 3e, and Figure 3f, respectively, and in the Supporting Information for six and eight qubits.…”

Native three-body interaction in superconducting circuits

“…c) Connecting the middle two nodes of the circuit to the ends of a mediating resonator couples the modes φ1 and φ2 to the resonator. sary to implement concrete quantum computations [47][48][49][50][51][52][53][54][55][56][57]. However, it is also possible to employ a set up, which actively chooses to only make use of exactly the states we have available in our system.…”

“…Hence, whether the XXC-coupling is turned on or off is completely determined by initialization and does not change during dynamics, barring noise effects. So working in the basis of |0 1 0 2 φ c , |1 1 0 2 φ c and |0 1 1 2 φ c with φ c = 0, 1, we may say that the system implements a gate represented by a diagonal matrix of phases when φ c = 0 and by U =   e iγ 0 0 0 0 e iδ 0 e iδ 0   (52) when φ c = 1. The phases are a simple consequence of the fact that the different states have different energies, and so acquire different trivial dynamical phases.…”

Kuantum Uyarlamalı Genetik Algoritmalar için Çözüm Kalitesini Artıracak Yeni Bir Yaklaşım

“…Kullanılan yapıtaşları ve genel prensipler farklı olduklarından dolayı, kuantum sistemlerin çalışması için temelde farklı yaklaşımlar gerekmektedir. Kuantum hesaplamada, klasik Boolean hesaplamalarında kullanılan "ve", "veya" ve "ya da" gibi operatörler yerine Hadamard, Pauli-X, Pauli-Y, Pauli-Z, Phase ve pi/8 gibi kuantum operatörleri kullanılmaktadır [27]. Donanımsal olarak kuantum kapısı olarak isimlendirilen bu operatörler, kübitler ile işleme girerek kübitlerin durum değiştirmesine neden olmaktadır.…”