arXiv subjects

Jun-Hao Liu

Publications and source records attributed to Jun-Hao Liu.

7 recordsLinked to original sources

arXiv2020

Tunable Optomechanically Induced Sideband Comb

Cavity optomechanical system can exhibit higher-order sideband comb effect when it is driven by a control field $ω_{c}$ and a probe field $ω_{p}$, and works in the non-perturbative regime, as was shown in a previous work [Xiong et al., Opt. Lett. 38, 353 (2013)]. The repetition frequency of such a comb is equal to the mechanical frequency $ω_{b}$ and is untunable, which limits the precision of the comb. Here we address this problem by driving the system with an additional strong probe field $ω_{f}$, and the detuning between $ω_{f}$ and $ω_{c}$ is equal to $ω_{b}/n$ (here $n$ is an integer), i.e., this detuning is a fraction of the mechanical frequency. In this case, we obtain some interesting results. We find that not only the integer-order (higher-order) sidebands, but also the fraction-order sidebands, and the sum and difference sidebands between the integer- and fraction-order sidebands, will appear in the output spectrum. The generated nonlinear sidebands constitute an optomechanically induced sideband comb (OMISC). The frequency range and the repetition frequency of the OMISC are proportional to the sideband cutoff-order number and the sideband interval, respectively. We show that we can extend the frequency range of the OMISC by increasing the intensity of the probe field $ω_{p}$. More importantly, we can decrease the repetition frequency, and consequently, improve the precision of the OMISC by increasing $n$ and the intensity of the probe field $ω_{f}$.

quant-ph↗

arXiv2019

Nonreciprocal transmission and fast-slow light effects in a cavity optomechanical system

We study the nonreciprocal transmission and the fast-slow light effects in a cavity optomechanical system, in which the cavity supports a clockwise and a counter-clockwise circulating optical modes, both the two modes are driven simultaneously by a strong pump field and a weak signal field. We find that when the intrinsic photon loss of the cavity is equal to the external coupling loss of the cavity, the system reveals a nonreciprocal transmission of the signal fields. However, when the intrinsic photon loss is much less than the external coupling loss, the nonreciprocity about the transmission properties almost disappears, and the nonreciprocity is shown in the group delay properties of the signal fields, and the system exhibits a nonreciprocal fast-slow light propagation phenomenon.

quant-ph↗

arXiv2018

Matter effects on the flavor conversions of solar neutrinos and high-energy astrophysical neutrinos

Can we observe the solar eclipses in the neutrino light? In principle, this is possible by identifying the lunar matter effects on the flavor conversions of solar neutrinos when they traverse the Moon before reaching the detectors at the Earth. Unfortunately, we show that the lunar matter effects on the survival probability of solar $^8{\rm B}$ neutrinos are suppressed by an additional factor of $1.2\%$, compared to the day-night asymmetry. However, we point out that the matter effects on the flavor conversions of high-energy astrophysical neutrinos, when they propagate through the Sun, can be significant. Though the flavor composition of high-energy neutrinos can be remarkably modified, it is quite challenging to observe such effects even in the next-generation of neutrino telescopes.

hep-ph↗

arXiv2018

A single-photon router based on a modulated cavity optomechanical system

We investigate the routing of a single-photon in a modulated cavity optomechanical system, in which the cavity is driven by a strong coupling field, and the mechanical resonator (MR) is modulated with a weak coherent field. We show that, when there is no a weak coherent field modulating the MR, the system cannot act as a single-photon router, since the signal will be completely covered by the quantum and thermal noises. By introducing the weak coherent field, we can achieve the routing of the single-photon by adjusting the frequency of the weak coherent field, and the system can be immune to the quantum and thermal noises.

quant-ph↗

arXiv2018

Controllable single-photon nonreciprocal transmission in a cavity optomechanical system with a weak coherent driving

We study the nonreciprocal transmission of a single-photon in a cavity optomechanical system, in which the cavity supports a clockwise and a counter-clockwise circulating optical modes, the mechanical resonator (MR) is excited by a weak coherent driving, and the signal photon is made up of a sequence of pulses with exactly one photon per pulse. We find that, if the input state is a single-photon state, it is insufficient to study the nonreciprocity only from the perspective of the transmission spectrums, since the frequencies where the nonreciprocity happens are far away from the peak frequency of the single-photon. So we show the nonreciprocal transmission behavior by comparing the spectrums of the input and output fields. In our system, we can achieve a transformation of the signal transmission from unidirectional isolation to unidirectional amplification in the single-photon level by changing the amplitude of the weak coherent driving. The effects of the mechanical thermal noise on the single-photon nonreciprocal transmission are also discussed.

quant-ph↗

arXiv2017

Another look at the impact of an eV-mass sterile neutrino on the effective neutrino mass of neutrinoless double-beta decays

The possible existence of an eV-mass sterile neutrino, slightly mixing with ordinary active neutrinos, is not yet excluded by neutrino oscillation experiments. Assuming neutrinos to be Majorana particles, we explore the impact of such a sterile neutrino on the effective neutrino mass of neutrinoless double-beta decays $\langle m \rangle^\prime_{ee} \equiv m^{}_1 |V^{}_{e1}|^2 e^{{\rm i}ρ} + m^{}_2 |V^{}_{e2}|^2 + m^{}_3 |V^{}_{e3}|^2 e^{{\rm i}σ} + m^{}_4 |V^{}_{e4}|^2 e^{{\rm i}ω}$, where $m^{}_i$ and $V^{}_{ei}$ (for $i = 1, 2, 3, 4$) denote respectively the absolute masses and the first-row elements of the 4$\times$4 neutrino flavor mixing matrix $V$, for which a full parametrization involves three Majorana-type CP-violating phases $\{ρ, σ, ω\}$. A zero effective neutrino mass $|\langle m \rangle^\prime_{ee}| = 0$ is possible no matter whether three active neutrinos take the normal or inverted mass ordering, and its implications for the parameter space are examined in great detail. In particular, given the best-fit values of $m^{}_4 \approx 1.3~{\rm eV}$ and $|V^{}_{e4}|^2 \approx 0.019$ from the latest global analysis of neutrino oscillation data, a three-dimensional view of $|\langle m \rangle^\prime_{ee}|$ in the $(m^{}_1, ρ)$-plane is presented and further compared with that of the counterpart $|\langle m \rangle^{}_{ee}|$ in the absence of any sterile neutrino.

hep-ph↗

arXiv2016

Majorana Neutrino Masses from Neutrinoless Double-Beta Decays and Lepton-Number-Violating Meson Decays

The Schechter-Valle theorem states that a positive observation of neutrinoless double-beta ($0νββ$) decays implies a finite Majorana mass term for neutrinos when any unlikely fine-tuning or cancellation is absent. In this note, we reexamine the quantitative impact of the Schechter-Valle theorem, and find that current experimental lower limits on the half-lives of $0νββ$-decaying nuclei have placed a restrictive upper bound on the Majorana neutrino mass $|δm^{ee}_ν| < 7.43 \times 10^{-29}~{\rm eV}$ radiatively generated at the four-loop level. Furthermore, we generalize this quantitative analysis of $0νββ$ decays to that of the lepton-number-violating (LNV) meson decays $M^- \to {M^\prime}^+ + \ell^-_α+ \ell^-_β$ (for $α$, $β$ = $e$ or $μ$). Given the present upper limits on these rare LNV decays, we have derived the loop-induced Majorana neutrino masses $|δm^{ee}_ν| < 9.7 \times 10^{-18}~{\rm eV}$, $|δm^{eμ}_ν| < 1.6 \times 10^{-15}~{\rm eV}$ and $|δm^{μμ}_ν| < 1.0 \times 10^{-12}~{\rm eV}$ from $K^- \to π^+ + e^- + e^-$, $K^- \to π^+ + e^- + μ^-$ and $K^- \to π^+ + μ^- + μ^-$, respectively. A partial list of radiative neutrino masses from the LNV decays of $D$, $D_s^{}$ and $B$ mesons is also given.

hep-ph↗