We propose a way to realize a multiqubit controlled-phase gate with one qubit simultaneously controlling n target qubits using atoms in cavity QED. In this proposal, there is no need to use classical pulses during the entire gate operation. The gate operation time scales as | $\sqrt {n}$ | only and thus the gate can be performed faster when compared with sending atoms through the cavity one at a time. In addition, only three operational steps are required to realize this n-target-qubit controlled-phase gate. This proposal is quite general and can be applied to other physical systems, such as various superconducting qubits coupled to a resonator, NV centers coupled to a microsphere cavity, or quantum dots in cavity QED.We propose a way to realize a multiqubit controlled-phase gate with one qubit simultaneously controlling n target qubits using atoms in cavity QED. In this proposal, there is no need to use classical pulses during the entire gate operation. The gate operation time scales as |$\sqrt {n}$| only and thus the gate can be performed faster when compared with sending atoms through the cavity one at a time. In addition, only three operational steps are required to realize this n-target-qubit controlled-phase gate. This proposal is quite general and can be applied to other physical systems, such as various superconducting qubits coupled to a resonator, NV centers coupled to a microsphere cavity, or quantum dots in cavity QED.

arXiv:1212.3059Progress of Theoretical and Experimental PhysicsFeb 1, 20130 citations

Realization of Three-Qubit Controlled-Phase Gate Operation with Atoms in Cavity QED System

Shi-Qing Tang, Deng-Yu Zhang, Xie Li-Jun +2 more

We propose a scheme for realization of three-qubit controlled-phase gate via passing two three-level atoms through a high-Q optical cavity in a cavity QED system. In the presented protocol, the two stable ground states of the atoms act as the two controlling qubits and the zero- and one-photon Fock states of the cavity-field form the target qubit, and no auxiliary state or any measurement is required. The numerical simulation shows that the gate fidelities remain at a high level under the influence of the atomic spontaneous emission, the decay of the cavity mode and deviation of the coupling strength. The experimental feasibility of our proposal is also discussed.We propose a scheme for realization of three-qubit controlled-phase gate via passing two three-level atoms through a high-Q optical cavity in a cavity QED system. In the presented protocol, the two stable ground states of the atoms act as the two controlling qubits and the zero- and one-photon Fock states of the cavity-field form the target qubit, and no auxiliary state or any measurement is required. The numerical simulation shows that the gate fidelities remain at a high level under the influence of the atomic spontaneous emission, the decay of the cavity mode and deviation of the coupling strength. The experimental feasibility of our proposal is also discussed.

Chinese Physics LettersFeb 1, 200910 citations

Cavity QED implementation of Three qubit quantum phase gate

Juntao Chang, Suhail Zubairy

Bulletin of the American Physical SocietyMar 4, 20050 citations

Three qubit quantum phase gate based on cavity QED

Juntao Chang, Muhammad Suhail Zubairy

APSOct 1, 20040 citations

Multiplex-controlled phase gate with qubits distributed in a multicavity system

Biao‐Liang Ye, Zhen-Fei Zheng, Chui‐Ping Yang

We present a way to realize a multiplex-controlled phase gate of $n\ensuremath{-}1$ control qubits simultaneously controlling one target qubit, with $n$ qubits distributed in $n$ different cavities. This multiqubit gate is implemented by using $n$ qutrits ( three-level natural or artificial atoms) placed in $n$ different cavities, which are coupled to an auxiliary qutrit. Here, the two logic states of a qubit are represented by the two lowest levels of a qutrit placed in a cavity. We show that this $n$ -qubit controlled phase gate can be realized using only $2n+2$ basic operations, i.e., the number of required basic operations only increases linearly with the number $n$ of qubits. Since each basic operation employs the qutrit-cavity or qutrit-pulse resonant interaction, the gate can be fast implemented when the number of qubits is not large. Numerical simulations show that a three-qubit controlled phase gate, which is executed on three qubits distributed in three different cavities, can be high-fidelity implemented by using a circuit QED system. This proposal is quite general and can be applied to a wide range of physical systems, with atoms, NV centers, quantum dots, or various superconducting qutrits distributed in different cavities. Finally, this method can be applied to implement a multiqubit controlled phase gate with atoms using a cavity. A detailed discussion on implementing a three-qubit controlled phase gate with atoms and one cavity is presented.We present a way to realize a multiplex-controlled phase gate of $n\ensuremath{-}1$ control qubits simultaneously controlling one target qubit, with $n$ qubits distributed in $n$ different cavities. This multiqubit gate is implemented by using $n$ qutrits ( three-level natural or artificial atoms) placed in $n$ different cavities, which are coupled to an auxiliary qutrit. Here, the two logic states of a qubit are represented by the two lowest levels of a qutrit placed in a cavity. We show that this $n$-qubit controlled phase gate can be realized using only $2n+2$ basic operations, i.e., the number of required basic operations only increases linearly with the number $n$ of qubits. Since each basic operation employs the qutrit-cavity or qutrit-pulse resonant interaction, the gate can be fast implemented when the number of qubits is not large. Numerical simulations show that a three-qubit controlled phase gate, which is executed on three qubits distributed in three different cavities, can be high-fidelity implemented by using a circuit QED system. This proposal is quite general and can be applied to a wide range of physical systems, with atoms, NV centers, quantum dots, or various superconducting qutrits distributed in different cavities. Finally, this method can be applied to implement a multiqubit controlled phase gate with atoms using a cavity. A detailed discussion on implementing a three-qubit controlled phase gate with atoms and one cavity is presented.

arXiv:1806.04559Physical Review AJun 25, 201816 citations

\sqrt {n}

| only and thus the gate can be performed faster when compared with sending atoms through the cavity one at a time. In addition, only three operational steps are required to realize this n-target-qubit controlled-phase gate. This proposal is quite general and can be applied to other physical systems, such as various superconducting qubits coupled to a resonator, NV centers coupled to a microsphere cavity, or quantum dots in cavity QED.

We present a way to realize a multiplex-controlled phase gate of $n\ensuremath{-}1$ control qubits simultaneously controlling one target qubit, with

n

qubits distributed in

n

different cavities. This multiqubit gate is implemented by using

n

qutrits ( three-level natural or artificial atoms) placed in

n

different cavities, which are coupled to an auxiliary qutrit. Here, the two logic states of a qubit are represented by the two lowest levels of a qutrit placed in a cavity. We show that this

n

-qubit controlled phase gate can be realized using only

2n+2

basic operations, i.e., the number of required basic operations only increases linearly with the number

n

of qubits. Since each basic operation employs the qutrit-cavity or qutrit-pulse resonant interaction, the gate can be fast implemented when the number of qubits is not large. Numerical simulations show that a three-qubit controlled phase gate, which is executed on three qubits distributed in three different cavities, can be high-fidelity implemented by using a circuit QED system. This proposal is quite general and can be applied to a wide range of physical systems, with atoms, NV centers, quantum dots, or various superconducting qutrits distributed in different cavities. Finally, this method can be applied to implement a multiqubit controlled phase gate with atoms using a cavity. A detailed discussion on implementing a three-qubit controlled phase gate with atoms and one cavity is presented.