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Zi-Qi Zhu

Publications and source records attributed to Zi-Qi Zhu.

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Triple top baryon $Ω_{ttt}$

The recent observation of toponium by CMS and ATLAS has renewed interest in top quark bound states. In this work, we present an exploratory but quantitative study of the hypothetical triple-top baryon, denoted as $Ω_{ttt}$, the only baryon that is governed by ultraviolet freedom. Using a variational method with an effective potential of $ttt$ that includes QCD, Higgs, and QED contributions, we estimate its mass to be around 514 GeV with a binding energy of about 4 GeV. We further discuss its possible production at future high-energy colliders, finding that the cross sections are extremely suppressed. The dominant weak decay channel is identified as $Ω_{ttt}\to W^+W^+W^+bbb$, leading to complex multi-lepton and multi-jet final states. Our analysis, though approximate, demonstrates the distinctive features of $Ω_{ttt}$ compared with other triply-heavy baryons such as $Ω_{ccc}$ and $Ω_{bbb}$, and may serve as a starting point for more refined approaches, including lattice QCD or effective field theory. This work highlights both the theoretical challenges and the potential opportunities in probing the strong interaction at unprecedented mass scales.

hep-ph

High sensitivity silicon carbide divacancy-based thermometer

Color centers in silicon carbide have become potentially versatile quantum sensors. Particularly, wide temperature range temperature sensing has been realized in recent years. However, the sensitivity is limited due to the short dephasing time of the color centers. In this work, we realize a high sensitivity silicon carbide divacancy-based thermometer using the thermal Carr-Purcell-Meiboom-Gill (TCPMG) method. First, the zero field splitting D of PL6 divacancy as a function of temperature is measured with a linear slope of -99.7 kHz/K. The coherence times of TCPMG pulses linearly increase with the pulse number and the longest coherence time is about 21 us, which is ten times larger than dephasing time. The corresponding temperature sensing sensitivity is 13.4 mK/Hz1/2, which is about 15 times higher than previous results. Finally, we monitor the laboratory temperature variations for 24 hours using the TCMPG pulse. The experiments pave the way for the applications of silicon carbide-based high sensitivity thermometer in the semiconductor industry, biology, and materials sciences.

quant-ph