arXiv subjects

Jian-Qi Zhang

Publications and source records attributed to Jian-Qi Zhang.

28 records · Page 2Linked to original sources

arXiv2014

Tunable single-photon multi-channel quantum router based on a hybrid optomechanical system

Routing of photon play a key role in optical communication networks and quantum networks. Although the quantum routing of signals has been investigated in various systems both in theory and experiment, the general form of quantum routing with multi-output terminals still needs to be explored. Here, we propose an experimentally accessible tunable single-photon multi-channel routing scheme using a optomechanics cavity coulomb coupling to a nanomechanical resonator. The router can extract a single-photon from the coherent input signal directly modulate into three different output channels. More important, the two output signal frequencies can be selected by adjusting Coulomb coupling strength. We also demonstrate the vacuum and thermal noise will be insignificant for the optical performance of the single-photon router at temperature of the order of 20 mK. Our proposal may have paved a new avenue towards multi-channel router and quantum network.

quant-ph↗

arXiv2014

Generating the Schrodinger cat state in a nanomechanical resonator coupled to a charge qubit

We propose a scheme for generating the Schrödinger cat state based on geometric operations by a nanomechanical resonator coupled to a superconducting charge qubit. The charge qubit, driven by two strong classical fields, interacts with a high-frequency phonon mode of the nanomechanical resonator. During the operation, the charge qubit undergoes no real transitions, while the phonon mode of the nanomechanical resonator is displaced along different paths in the phase space, dependent on the states of the charge qubit, which yields the Schrödinger cat state. The robustness of the scheme is justified by considering noise from environment, and the feasibility of the scheme is discussed.

cond-mat.mes-hall↗

arXiv2014

Phase-controlled Fano resonance by the nanoscale optomechanics

Observation of the Fano line shapes is essential to understand properties of the Fano resonance in different physical systems. We explore a tunable Fano resonance by tuning the phase shift in a Mach-Zehnder interferometer (MZI) based on a single-mode nano-optomechanical cavity. The Fano resonance is resulted from the optomechanically induced transparency caused by a nano-mechanical resonator and can be tuned by applying an optomechanical MZI. By tuning the phase shift in one arm of the MZI, we can observe the periodically varying line shapes of the Fano resonance, which represents an elaborate manipulation of the Fano resonance in the nanoscale optomechanics.

physics.optics↗

arXiv2013

Fast optical cooling of nanomechanical cantilever with the dynamical Zeeman effect

We propose an efficient optical electromagnetically induced transparency (EIT) cooling scheme for a cantilever with a nitrogen-vacancy center attached in a non-uniform magnetic field using dynamical Zeeman effect. In our scheme, the Zeeman effect combined with the quantum interference effect enhances the desired cooling transition and suppresses the undesired heating transitions. As a result, the cantilever can be cooled down to nearly the vibrational ground state under realistic experimental conditions within a short time. This efficient optical EIT cooling scheme can be reduced to the typical EIT cooling scheme under special conditions.

quant-ph↗

arXiv2013

Cooling a charged mechanical resonator with time-dependent bias gate voltages

We show a purely electronic cooling scheme to cool a charged mechanical resonator (MR) down to nearly the vibrational ground state by elaborately tuning bias gate voltages on the electrodes, which couple the MR by Coulomb interaction. The key step is the modification of time-dependent effective eigen-frequency of the MR based on the Lewis-Riesenfeld invariant. With respect to a relevant idea proposed previously [Li et al., Phys. Rev. A 83, 043803 (2011)], our scheme is simpler, more practical and completely within the reach of current technology.

quant-ph↗

arXiv2012

Precision measurement of charge number with optomechanically induced transparency

We propose a potentially practical scheme to precisely measure the charge numbers of small charged objects by optomechanical systems using optomechanically induced transparency (OMIT). In contrast to the conventional measurements based on the noise backaction on the optomechanical systems, our scheme makes use of the small deformation of the mechanical resonator sensitive to the charge number of the nearby charged object, which could achieve the detection of a single charge. The relationship between the charge number and the window width of the OMIT is investigated and the feasibility of the scheme is justified by numerical simulation using currently available experimental values.

quant-ph↗

arXiv2011

An unconventional geometric phase gate with two nonresonant quantum dots trapped in a photonic crystal cavity

We propose a scheme for realizing a two-qubit controlled phase gate via an unconventional geometric phase with two nonresonant quantum dots trapped in a photonic crystal cavity. In this system, the quantum dots simultaneously interact with a large detuned cavity mode and strong driving classical light fields. During the gate operation, the quantum dots undergo no transitions, while the cavity mode is displaced along a closed path in the phase space. In this way, the system can acquire geometric phases conditional upon the states of the quantum dots. After implementing single-qubit operations, a two-qubit controlled phase gate can be constructed.

quant-ph↗

arXiv2011

Two-qubit controlled phase gate based on two nonresonant quantum dots trapped in a coupled-cavity array

We propose a scheme for realizing quantum controlled phase gates with two nonidentical quantum dots trapped in two coupled photonic crystal cavities and driven by classical laser fields under the condition of non-small hopping limit. During the gate operation, neither the quantum dots are excited, while the system can acquire different phases conditional upon the different states of the quantum dots. Along with single-qubit operations, a two-qubit controlled phase gate can be achieved.

quant-ph↗

arXiv2011

The scalable quantum computation based on quantum dot systems

We propose a scheme for realizing the scalable quantum computation based on nonidentical quantum dots trapped in a single-mode waveguide. In this system, the quantum dots simultaneously interact with a large detuned waveguide and classical light fields. During the process, neither the waveguide mode nor the quantum dots are excited, while the sub-system composed of any two quantum dots can acquire phases conditional upon the states of these two quantum dots and the certain detunings between the waveguide mode and corresponding external light fields. Therefore, it can be used to realize selective quantum phase gates, graph states, $N$-qubit controlled phase $π$ gates, and cluster states.

quant-ph↗

arXiv2011

Quantum controlled phase gate based on two nonresonant quantum dots trapped in two coupled photonic crystal cavities

We propose a scheme for realizing two-qubit quantum phase gates with two nonidentical quantum dots trapped in two coupled photonic crystal cavities and driven by classical laser fields. During the gate operation, neither the cavity modes nor the quantum dots are excited, so the decoherence can be suppressed. The system can acquire a phase conditional upon the states of the quantum dots, which can be used to realize the controlled phase gate.

quant-ph↗