arXiv subjects

Jing-Jing Liu

Publications and source records attributed to Jing-Jing Liu.

15 recordsLinked to original sources

arXiv2023

Acoustic meta-stethoscope for cardiac auscultation

Straight cylindrical stethoscopes serve as an important alternative to conventional stethoscopes whose application in the treatment of infectious diseases might be limited by the use of protective clothing. Yet their miniaturization is challenging due to the low-frequency of bioacoustics signal. Here, we design and experimentally implement a meta-stethoscope with subwavelength size, simple fabrication, easy assembly yet high sensitivity, which simply comprises multiple round perforated plate units and a cylindrical shell. We elucidate our proposed mechanism by analytically deriving the frequency response equation, which proves that the equivalent acoustic propagation path is substantially increased by the high-index metamaterial, enabling downscaling of the meta-stethoscope to subwavelength footprint. The acoustic performance of meta-stethoscope is experimentally characterized by monitoring the cardiac auscultation on clothed human body. The simulated and measured results agree well, with both showing the expected enhancement of sensitivity of our proposed meta-stethoscope (~ 10 dB) within the predicted working frequency range from 80 to 130 Hz despite its compactness and simplicity. Our designed portable, detachable yet effective meta-stethoscope opens a route to metamaterial-enabled stethoscope paradigm, with potential applications in diverse scenarios such as medical diagnosis and acoustic sensing.

physics.app-ph↗

arXiv2020

A Magnetic-Monopole-Based Mechanism to the formation of the Hot Big Bang Modeled Universe

There are some particle physics theories that go beyond the so-called "standard cosmological model" to predict the existence of magnetic monopoles\,(MMs). The discovery of magnetic monopoles would be an incredible breakthrough in high-energy physics. The existence of MMs in the early Universe has been speculated and anticipated from Grand Unified Theory. If MMs exist, the inverse powers of the unification mass will not suppressed the baryon number violating effects of grand unified gauge theories. Therefore, MM catalyzing nucleon decay is a typical strong interaction. This phenomenon is due to the boundary conditions that must be imposed on the core of MM fermion fields. We present a possible mechanism to explain the formation of the Hot Big Bang Cosmology. The main ingredient in our model is nucleon decay catalyzed by magnetic monopoles (i.e., the Rubakov-Callan effect). It is shown that Hot Big Bang developed naturally, because the luminosity due to the Rubakov-Callan effect is much greater than the Eddington luminosity (i.e., $L_m>10^4L_{\rm{Edd}}$).

physics.gen-ph↗

arXiv2018

The Physical Essence of Pulsar Glitch

Based on the magnetic dipole radiation from the 3P2 neutron superfluid vortices (3P2NSFV) in neutron stars, we propose a model of glitch for young pulsars by oscillation between B phase and A phase of 3P2 Neutron superfluid. The main behavior of glitches of pulsars may be naturally explained by our model.

astro-ph.HE↗

arXiv2018

Supernova β^- decay of nuclides 53Fe, 54Fe, 55Fe, and 56Fe in strongly screened plasma

The electron screening strong effect on the electron energy and threshold energy of the beta decay reaction. in this paper, we study the $β^-$ decay rates of some iron isotopes. The electron screening beta decay rates increase by about two orders of magnitude. The strong screening beta decay rates due to Q-value correction are by more than one order of magnitude higher than those of without Q-value correction.

nucl-th↗

arXiv2017

A unified model of supernova driven by magnetic monopoles

In this paper, we first discuss a series of important but puzzling physical mechanisms concerning the energy source, various kinds of core collapsed supernovae explosion mechanisms during central gravitational collapse in astrophysics. We also discuss the puzzle of possible association of $γ$-ray burst with gravitational wave perturbation, the heat source for the molten interior of the core of the earth and finally the puzzling problem of the cooling of white dwarfs. We then make use of the estimations for the space flux of magnetic monopoles (hereafter MMs) and nucleon decay induced by MMs (called the Rubakov-Callen(RC) effect) to obtain the luminosity due to the RC effect. In terms of the formula for this RC luminosity, we present a unified treatment for the heat source of the Earth's core, the energy source for the white dwarf interior, various kinds of core collapsed supernovae (Type II Supernova (SNII), Type Ib Supernova (SNIb), Type Ic Supernova (SNIc), Super luminous supernova (SLSN)), and the production mechanism for $γ$-ray burst. This unified model can also be used to reasonably explain the possible association of the short $γ$-ray burst detected by the Fermi $γ$-ray Burst Monitoring Satellite (GBM) with the LIGO gravitational wave event GW150914 in September 2015.

astro-ph.HE↗

arXiv2017

Resonant nuclear reaction $^{23}$Mg $(p,γ)$ $^{24}$Al in strongly screening magnetized neutron star crust

Basing on the relativistic theory in superstrong magnetic fields (SMFs), we investigate the influence of strong electron screening (SES) on the rates of nuclear reaction $^{23}$Mg $(p, γ)$ $^{24}$Al by three models of Lai (LD), Fushiki et al. (FGP), and Liu et al. (LJ) on the surface of magnetars. Our results show that the rates can be greatly enhanced by three orders of magnitude due to the influence of SES. The rates in our model are in good agreement with those of LD and FGP at relatively low density environment (e.g. $ρ_7<0.01$) for $1 10^2$), the rates of our model can be 1.58 times and around three orders of magnitude larger than those of FGP and LD, respectively. The significant increase of the rates of our model for $^{23}$Mg $(p, γ)$ $^{24}$Al implies that more $^{23}$Mg will escape from the Ne-Na cycle due to SES in SMFs. As a consequence, the next reaction $^{24}$Al $(β^+, ν)$ $^{24}$Mg will produce more $^{24}$Mg to participate in the Mg-Al cycle. Thus, it may lead to synthesize a large amount of production of $A\geq 20$ nuclides (e.g. $^{26}$Al) on the surface of magnetars. These heavy elements (e.g. $^{26}$Al) may be thrown out due to the compact binary mergers of double neutron star (NS-NS) or black hole and neutron star (BH and NS) systems. Our results may help to understand why the $^{26}$Al is always overabundance in the interstellar space. Our conclusion may be helpful to the investigation of the nucleosynthesis of some heavy elements, the energy generation rate, and the numerical calculations of magnetars evolution.

nucl-th↗

arXiv2017

Strongly screening on electron capture for Nuclides $^{52, 53, 59, 60}$Fe by the Shell-Model Monte Carlo method in pre-supernova

The death of the massive stars due to supernova explosion is a key ingredient in stellar evolution, stellar population synthesis. The electron capture (EC) plays a vital role in supernovae explosions. According to the Shell-Model Monte Carlo (SMMC) method, basing onthe Random Phase Approximation (RPA) and Linear Response Theory Model (LRTM), we study the strongly screening EC rates of nuclides $^{52, 53, 59, 60}$Fe in presupernova. The results show that the screening rates can decrease about 18.66\%. We compare our results with those of Fuller et al. (FFN), Aufderheide et al. (AUFD), and Nabi et al. (NKK)in the case with and without strong electron screening(SES). For the case without SES, our calculations are in very good agreement with those of AUFD in relatively high density surroundings and the maximum error is within 0.35\% at $ρ_7=100$ (e. g., even-even nuclei $^{60}$Fe). However, for odd-A nuclei$^{59}$Fe, our rates are close to one, one, two order magnitude smaller than those of FFN, AUFD, and NKK. For the case with SES, our screening results are about three, two orders magnitude, and 7.27\% lower than those of FFN, AUFD, NKK for $^{60}$Fe, respectively, and it is lower about two, two orders magnitude, and 12.42\% than those of FFN, AUFD, NKK for odd-A nuclide $^{59}$Fe.

nucl-th↗

arXiv2017

Strongly screening electron capture rates of chromium isotopes in presupernova

Taking into account the effect of electron screening on the electron energy and electron capture threshold energy, by using the method of Shell-Model Monte Carlo and Random Phase Approximation theory, we investigate the strong electron screening capture rates of chromium isotopes according to the linear response theory screening model. The strong screening rates can decrease by about 40.43\% (e.g., for $^{60}$Cr at $T_9=3.44,Y_e=0.43$). Our conclusions may be helpful to the researches of supernova explosion and numerical simulation.

nucl-th↗

arXiv2017

Some New Possible Anticipated Signals for Existence of Magnetic Monopoles

We summarize some predictions from the model of supermassive object with magnetic monopoles which match up with recent astronomical observations quantitatively. They may be the signals for existence of magnetic monopoles in the supermassive objects, such as one at the Galactic Center.

astro-ph.HE↗

arXiv2016

A possible influence on standard model of quasars and active galactic nuclei in strong magnetic field

Recent observational evidence indicates that the center of our Milky Way harbours a super-massive object with ultra-strong radial magnetic field (Eatough et al., 2013). Here we demonstrate that the radiations observed in the vicinity of the Galactic Center (GC) (Falcke and Marko 2013) cannot be emitted by the gas of the accretion disk since the accreting plasma is prevented from approaching to the GC by the abnormally strong radial magnetic field. These fields obstruct the infalling accretion flow from the inner region of the disk and the central massive black hole in the standard model. It is expected that the observed radiations near the Galactic Center cannot be generated by the central black hole. We also demonstrate that the observed ultra-strong radial magnetic field near the Galactic Center ( Eatough et al., 2013) cannot be generated by the - turbulence dynamo mechanism of Parker since preliminary qualitative estimate in terms of this mechanism gives a magnetic field strength six orders of magnitude smaller than the observed field strength at . However, both these difficulties or the dilemma of the standard model can be overcome if the central black hole in the standard model is replaced by a supper-massive stellar object containing magnetic monopoles ( SMSOMM, Peng and Chou, 2001). The observed power peaking of the thermal radiation is essentially the same as our theoretical prediction. In addition, the discovery of the ultra-strong radial magnetic field near the Galactic Center can be naturally explained and is consistent with the prediction of our model( Peng and Chou 2001). Furthermore, the observed ultra-strong radial magnetic field in the vicinity of the Galactic Center may be considered as the astronomical evidence for the existence of magnetic monopoles as predicted by the Grand Unified Theory of particle physics.

astro-ph.GA↗

arXiv2016

A new insight into neutrino energy loss by electron capture of iron group nuclei in magnetars surface

Based on the relativistic mean-field effective interactions theory, and Lai dong model \citep{b37, b38, b39}, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetars surface. By using the method of Shell-Model Monte Carlo (SMMC), and the Random Phase Approximation (RPA) theory, we detailed analyze the neutrino energy loss rates(NELRs) by electron capture (EC) for iron group nuclei in SMFs.

astro-ph.HE↗

arXiv2016

Strong screening effects on resonant nuclear reaction $^{23}$Mg $(p,γ)$ $^{24}$Al in the surface of magnetars

Based on the theory of relativistic superstrong magnetic fields(SMFs), by using the method of the Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening(SES) in SMFs, and the influence of SES on the nuclear reaction of $^{23}$Mg $(p, γ)$$^{24}$Al. Our calculations show that the nuclear reaction will be markedly effected by the SES in SMFs in the surface of magnetars. Our calculated screening rates can increase two orders of magnitude due to SES in SMFs.

astro-ph.SR↗

arXiv2013

Electron capture of iron group nuclei in magnetars

Using the theory of relativity in superstrong magnetic fields (SMFs) and nuclear shell model, we carry out estimation for electron capture (EC) rates on iron group nuclei in SMFs. The rates of change of electronic abundance (RCEA) due to EC are also investigated in SMFs. It is concluded that the EC rates of most iron group nuclides are increased greatly by SMFs and even exceeded by nine orders of magnitude. On the other hand, RCEA is influenced greatly by SMFs and even reduced by more than eight orders of magnitude in the EC reaction.We also compare our results with those of Fuller et al.(FFN) and Aufderheide et al.(AUFD) in the case with and without SMFs. The results show that our results are in good agreement with AUFD's, but the rates of FFN's are about close to one order of magnitude bigger than ours in the case without SMFs. On the contrary, our calculated rates for most nuclides in SMFs are increased and even exceeded as much as for nine and eight orders of magnitude of compared to FFN's and AUFD's results, which is in the case without SMFs, respectively.

astro-ph.HE↗

arXiv2013

Electron capture of strongly screening nuclides $^{56}$Fe, $^{56}$Co, $^{56}$Ni , $^{56}$Mn ,$^{56}$Cr and $^{56}$V in presupernova

According to the Shell-Model Monte Carlo method, basing on the Random Phase Approximation and the linear response theory, we carried out an estimation on electron capture of strongly screening nuclides $^{56}$Fe, $^{56}$Co, $^{56}$Ni , $^{56}$Mn ,$^{56}$Cr and $^{56}$V in strong electron screening (SES)in presupernova. The EC rates are decreased greatly and even exceed $21.5\%$ in SES. We also compare our results with those of Aufderheide (AFUD), which calculated by the method of Aufderheide in SES. Our results are agreed reasonably well with AUFD at higher density-temperature surroundings (e.g. $ρ_7>60, T_9=15.40$) and the maximum error is $\sim $0.5$\%$. However, the maximum error is $\sim $13.0$\%$ at lower density surroundings (e.g. $^{56}$Cr at $ρ_7=10, T_9=15.40, Y_e=0.41$ ). On the other hand, we also compared our results in SES with those of FFN's and Nabi's, which is in the case without SES. The comparisons show that our results are lower more than one order magnitude than FFN's, but about $7.23\%$ than Nabi's.

astro-ph.HE↗

arXiv2004

Higgs boson pair production in the little Higgs model at hadron colliders

The Higgs boson pair production process at hadron collider provides an opportunity for performing a study of the trilinear Higgs boson self-coupling. In this paper, we analyze the pair production of a neutral Higgs boson via both gluon-gluon and $b$-$\bar{b}$ fusions in the littlest Higgs (LH) model at the CERN LHC. We find that in some parameter space the relative corrections of the total cross section to the SM prediction may reach a value of 24% when $x ~ (=4 f v'/v^2)=0.95$ at the LHC. We conclude that if the parameter $x$ has a value above 0.8, the relative corrections contributed by the LH model reach values beyond 8% and can be observed at the LHC.

hep-ph↗