Ramsey spectroscopy

Norman F. Ramsey, Spectroscopy with Coherent Radiation Selected Papers of Norman F. Ramsey with Commentary (Singapore M>rld Scientific, 1998), p. 205. 

The increased spectral resolution obtained with the Ramsey technique because of the increased interaction time allows the direct observation of recoil doublets in atomic or molecular transitions (Sect. 9.1.1). An example is the Ramsey spectroscopy of the intercombination line in calcium at k = 657 nm [1268], where a linewidth... 

The combination of Ramsey spectroscopy (see Sect. 9.3) and squeezed light has brought an increased spectral resolution. While traditional Ramsey spectroscopy allows the resolution Am = 2nl2>T where T is the flight time of the molecules between the two separated fields, using two-mode squeezed light and two-atom excitation with joint detection a spectral resolution oin/3T could be achieved [1355]. 

A. Huber, B. Gross, M. Weitz, Th.W. Hansch, Two-photon optical Ramsey spectroscopy of the 1S-2S transition in atomic hydrogen. Phys. Rev. A 58, R2631 (1998) ... 

B. Gross, A. Huber, M. Niering, M. Weitz, T.W. Hansch, Optical Ramsey spectroscopy of atomic hydrogen. Europhys. Lett. 44, 186... 

K. Qu, G.S. Agaral, Ramsey spectroscopy using squeezed light. Opt. Lett. 38,2563 (2013)... 

Once the kinetic energy has been reduced to a few raK, the earth s gravitational field could be used to further slow the atoms in an atomic "fountain," so that the projectiles can be observed for extended periods in free fall near the turning point of their parabolic trajectories. Optical two-photon Ramsey spectroscopy of such freely falling atoms is possible with a single standing wave laser field which the atoms traverse on their way up and again on their way down (Fig. 9). >25 as in ordinary Ramsey... 

Fig. 9. Scheme for optical Ramsey spectroscopy of an atomic fountain.24,25... 

In conventional Ramsey spectroscopy of a two-level system [50], two short n/2 pulses are applied in succession. If the second pulse comes immediately after the first, the transition is completed and all the population is excited. If instead there is a delay time T between the two pulses, which is long compared to the pulse duration x, the transition probability becomes sensitive to small differences between the radiofrequency frequency and the molecular transition frequency. The internal coherence evolving at the transition frequency accumulates a phase between pulses of whereas the rf field evolves a phase coT. When the difference between these two reaches it, the second pulse reverses the effect of the first, returning all the population to the initial state. More generally, the probability that a molecule will end up in the excited state is... 

R.G. Beausoleil, T.W. Hansch Two-photon optical Ramsey spectroscopy of freely falling atoms. Opt. Lett. 10, 547 (1985)... 

R.G. Beausoieil, T.W. Hansch Ultra-high-resolution two-photon optical Ramsey spectroscopy of an atomic fountain. Phys. Rev. A 33, 1661 (1986) M. A. Kasevich, E. Riis, S. Chu, R.G. DeVoe RF spectroscopy in an atomic fountain. Phys. Rev. Lett. 63, 612 (1989)... 

F. Riehle, Th. Kisteers, A. White, J. Helmecke, Ch.J. Borde Optical Ramsey spectroscopy in a rotating frame Sagnac effect in a matter-wave interferometer. Phys. Rev. Lett. 67, 177 (1991)... 

Fig. 6.9 Schematic represenation of the apparatus to perform quantum logic gates by atomic Ramsey spectroscopy.

Fig. 6.10 The three steps of a quantum gate with atomic Ramsey spectroscopy. Firstly, the state of an atom (first qubit) is transferred to the cavity mode. Secondly, the second atom (second qubit) undergos a conditional phase-shift depending on the state of the atom. Thirdly, the photon field is mapped back onto a third atom (replica of the first qubit).

Resonance, similar to that in pyrylium salts, was shown594,595 to exist between oxonium ion (299a) and carbenium ion (299b) forms in alkylated ketones, esters, and lactones that were obtained via alkylation with trimethyl- or triethyloxonium tetra-fluoroborates596 [Eq. (3.78)]. Ramsey and Taft597 used H NMR spectroscopy to investigate the nature of a series of secondary and tertiary carboxonium ions (300-302). 

Ramsey and Taft (10) have provided the first evidence by nmr spectroscopy that the aimethoxycarbonium salt of methyl acetate exists in the EZ form (11) only. It was later found that at -30 to -80°C, there is predominance... 

Some reviews [5-7] have appeared on NCE-electrospray ionization-mass spectrometry (NCE-ESI-MS) discussing various factors responsible for detection. Recently, Zamfir [8] reviewed sheathless interfacing in NCE-ESI-MS in which the authors discussed several issues related to sheathless interfaces. Feustel et al. [9] attempted to couple mass spectrometry with microfluidic devices in 1994. Other developments in mass spectroscopy have been made by different workers. McGruer and Karger [10] successfully interfaced a microchip with an electrospray mass spectrometer and achieved detection limits lower than 6x 10-8 mole for myoglobin. Ramsey and Ramsey [11] developed electrospray from small channels etched on glass planar substrates and tested its successful application in an ion trap mass spectrometer for tetrabutylammonium iodide as model compound. Desai et al. [12] reported an electrospray microdevice with an integrated particle filter on silicon nitride. 

Ramsey, M. H., Coles, B. J. (1988). Paper presented at 4th Biennial National Atomic Spectroscopy Symposium, York. 

M.A. El-Sayed. In A.D. Ramsey and D.A. Ramsay, editors, MTP International Review of Science, Spectroscopy, page 119. Butterworth, London, 1972. 

Nuclear magnetic resonance has become central in the work of chemists. The cover story of the November 5, 1984 Chemical and Engineering News dealt with NMR spectroscopy. In it NMR was portrayed as a powerful and indispensable tool for obtaining new chemical information. NMR is a powerful tool for chemists because an atom like hydrogen, with a tiny magnetic moment in its nucleus, becomes a sensitive probe within a molecule. Norman Ramsey showed theoretically that the resonance fi equency of a... 

Barshick C. M., Shaw R. W., Young J. P. and Ramsey J. M. (1994) Istopic analysis of uranium using glow discharge optogalvanic spectroscopy and diode lasers, Anal Chem 66 4154-4158. 

Steps (la) and (Ic) can be regarded as two resonant pulses (of opposite phase) in the Ramsey separated-field method of spectroscopy [52]. We can see that if step (b) is active (thereby changing the agn of the 11 > n=l) component of the wave fiinction) then a spin flip is produced by the Ramsey fields. If aep (lb) is inactive, the net effect of the Ramsey fields is to leave the spin state unchanged. This CN operation can be incorporated to provide an overall CN operation between two ions in an ensemble of N ions if we choose the ion oscillator mode to be the center-of-mass (COM) mode of the ensemble. Specifically, to realize a controlled-not C k between two ions (m = control bit, k = target bit), we first assume the COM is prepared in the zero-point aate. The initial state of the system is therefore given by... 

One of the most important yet simple ideas that ignited excitement about fem-tochemistry is wavepacket interferometry (Salour and Cohen-Tannoudji, 1977 Scherer, et al., 1990, 1991, 1992 Jonas and Fleming, 1995 Weinacht, et al., 1999), an optical form of Ramsey-fringe spectroscopy (Ramsey, 1990). A molecular system is subjected to two identical optical pulses created by splitting one pulse at a beam splitter. The two pulses are called the pump and the probe . The time delay between pump and probe pulses is scanned systematically using an optical delay line. The optical arrangement is very similar to that of a Fourier Transform Spectrometer (Heller, 1990). The difference in the paths traveled by the pump and probe pulses, Ad, before the two pulses are recombined at a second beam splitter corresponds to a time delay, At = Ad/c, where c is the speed of light. 

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