Whispering gallery mode (WGM) microresonators have been intensively studied in many areas such as sensing, lasing, and fundamental study. WGM microresonators are always coupled by a tapered fiber, and the coupling is controlled by a 3D nanotranslation stage. We always suffer from the instability of coupling condition, which means it is difficult to put microresonators in practical applications. Hence, we present an efficient way to package on-chip ultrahigh-Q microresonators. Stimulated Raman Scattering is achieved in this packaged microresonator, which means we have a portable, narrow linewidth laser and it can be used to expand the working wavelength of a laser. In addition, by coupling two whispering-gallery modes (WGM), which is simultaneously excited in the packaged microtoroid resonator, we can observe an electromagnetically induced transparency (EIT) effect for the first time in a portable WGM structure. This packaged microresonator can be used for real quantum communication applications. Furthermore, highly sensitive sensing can benefit from the high Q-factor and its stability.
Practical quantum systems are open systems due to interactions with their environment. Understanding the evolution of open systems dynamics is important for quantum noise processes , designing quantum error correcting codes, and performing simulations of open quantum systems. Here we proposed an efficient quantum algorithm for simulating the evolution of an open quantum system on a duality quantum computer. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality algorithm, the time evolution of open quantum system is realized by using Kraus operators which is naturally realized in duality quantum computing. Compared to the Lloyd's quantum algorithm [Science.273, 1073(1996)] , the dependence on the dimension of the open quantum system in our algorithm is decreased. Moreover, our algorithm uses a truncated Taylor series of the evolution operators, exponentially improving the performance on the precision compared with existing quantum simulation algorithms with unitary evolution operations.