相关论文: Microwave spectroscopy of Lambda-doublet transitio…
Many modern theories predict that the fundamental constants depend on time, position, or the local density of matter. We develop a spectroscopic method for pulsed beams of cold molecules, and use it to measure the frequencies of microwave…
We estimate sensitivity coefficients to variation of the fine-structure constant alpha and electron-to-proton mass ratio mu for microwave Lambda-type transitions in CH molecule and for inversion-rotational transitions in partly deuterated…
The CH radical offers a sensitive way to test the hypothesis that fundamental constants measured on earth may differ from those observed in other parts of the universe. The starting point for such a comparison is to have accurate laboratory…
Analyzing weak microwave signals in the GHz regime is a challenging task if the signal level is very low and the photon energy widely undefined. A superconducting qubit can detect signals in the low photon regime, but due to its discrete…
We report precise measurements of ground-state, $\lambda$-doublet microwave transitions in the hydroxyl radical molecule (OH). Utilizing slow, cold molecules produced by a Stark decelerator we have improved over the precision of the…
Microwave and submillimeter molecular transition frequencies between nearly degenerated rotational levels, tunneling transitions, and mixed tunneling-rotational transitions show an extremely high sensitivity to the values of the…
We describe the so-called "Lambda-Zeeman method" to investigate individual hyperfine transitions between Zeeman sublevels of atoms in an external magnetic field of 0.1 mT - 0.25 T. Atoms are confined in a nanocell with thickness L = Lambda,…
Precise molecular transition frequencies are of great interest in the test of fundamental physics and also in various applications. Two well isolated ro-vibrational transitions of $^{12}$C$^{16}$O at 1.57 $\mu$m, R(9) and R(10) in the…
Using a Ramsey-type setup, the lambda-doublet transition in the $J=1,\, \Omega=1$ level of the $a^3\Pi$ state of CO was measured to be 394 064 870(10) Hz. In our molecular beam apparatus, a beam of metastable CO is prepared in a single…
We investigate phase-sensitive interference effects in a periodically $\sin(2\pi f_{\rm rf} t)$-driven, artificial two-state system connected to a microwave resonator at $f_{LC} \simeq 800$ MHz. We observe two kinds of multiphoton…
Motivated by recent experiments on quantum mechanical charge pumping in a Cooper pair sluice, we present a measurement scheme for observing shifts of transition frequencies in two-level quantum systems induced by broadband environmental…
We report the measurement of sub-Doppler double-resonance transitions in methane using a 3.3 $\mu$m continuous wave optical parametric oscillator to pump transitions in the fundamental $\nu_3$ band and a 1.67 $\mu$m frequency comb to probe…
The diatomic free radical methylidyne (CH) is an important tracer of the interstellar medium and the study of it was critical to our earliest understanding of star formation. Although it is detectable across the electromagnetic spectrum,…
$\Lambda$-doublet spectra of light diatomic radicals have high sensitivity to the possible variations of the fine structure constant alpha and electron-to-proton mass ratio beta. For molecules OH and CH sensitivity is further enhanced…
This work presents mm-Wave and sub-THz chip-to-package transitions for communications systems. To date, reported transitions either have high loss, typically 3 to 4 dB, or require high cost packages to support very fine bump pitches and low…
The sensitivity of rotational transitions in CH and CD to a possible variation of fundamental constants has been investigated. Largely enhanced sensitivity coefficients are found for specific transitions which are due to accidental…
A charge-density-wave (CDW) is characterized by a dynamical order parameter consisting of a time-dependent amplitude and phase, which manifest as optically-active collective modes of the CDW phase. Studying the behaviour of such collective…
Sensitivity to temporal variation of the fundamental constants may be strongly enhanced in transitions between narrow close levels of different nature. This enhancement may be realized in a large number of molecules due to cancelation…
The methoxy radical, CH$_3$O, has long been studied experimentally and theoretically by spectroscopists because it displays a weak Jahn-Teller effect in its electronic ground state, combined with a strong spin-orbit interaction. In this…
The propagation of a weak optical pulse through an atomic system in closed $\Lambda$ configuration is investigated in which the hyper fine levels are coupled by a microwave pulse. Under three photon resonance condition, it is observed that…