45,659 research outputs found
Building a 3.5 m prototype interferometer for the Q & A vacuum birefringence experiment and high precision ellipsometry
We have built and tested a 3.5 m high-finesse Fabry-Perot prototype
inteferometer with a precision ellipsometer for the QED test and axion search
(Q & A) experiment. We use X-pendulum-double-pendulum suspension designs and
automatic control schemes developed by the gravitational-wave detection
community. Verdet constant and Cotton-Mouton constant of the air are measured
as a test. Double modulation with polarization modulation 100 Hz and
magnetic-field modulation 0.05 Hz gives 10^{-7} rad phase noise for a 44-minute
integration.Comment: This draft has been presented in the 5th Edoardo Amaldi Conference on
Gravitational Wave
Symmetry-Breaking and Symmetry-Restoring Dynamics of a Mixture of Bose-Einstein Condensates in a Double Well
We study the coherent nonlinear tunneling dynamics of a binary mixture of
Bose-Einstein condensates in a double-well potential. We demonstrate the
existence of a new type of mode associated with the "swapping" of the two
species in the two wells of the potential. In contrast to the symmetry breaking
macroscopic quantum self-trapping (MQST) solutions, the swapping modes
correspond to the tunneling dynamics that preserves the symmetry of the double
well potential. As a consequence of two distinct types of broken symmetry MQST
phases where the two species localize in the different potential welils or
coexist in the same well, the corresponding symmetry restoring swapping modes
result in dynamics where the the two species either avoid or chase each other.
In view of the possibility to control the interaction between the species, the
binary mixture offers a very robust system to observe these novel effects as
well as the phenomena of Josephson oscillations and pi-mode
A Mesoscopic Resonating Valence Bond system on a triple dot
We introduce a mesoscopic pendulum from a triple dot. The pendulum is
fastened through a singly-occupied dot (spin qubit). Two other strongly
capacitively islands form a double-dot charge qubit with one electron in excess
oscillating between the two low-energy charge states (1,0) and (0,1); this
embodies the weight of the pendulum. The triple dot is placed between two
superconducting leads as shown in Fig. 1. Under well-defined conditions, the
main proximity effect stems from the injection of resonating singlet (valence)
bonds on the triple dot. This gives rise to a Josephson current that is charge-
and spin-dependent. Consequences in a SQUID-geometry are carefully
investigated.Comment: final version to appear in PR
An optimum design of a double pendulum in autoparametric resonance for energy harvesting applications
In this paper energy harvesting from vibrating surfaces through electromagnetic induction is addressed. A double pendulum subject to base excitations generates electrical energy through energy harvesting coils mounted on the pendulum masses. Optimum double pendulum generates energy at a rate of 9 mW for excitation parameters characteristic of bridge vibration, frequency of 2 Hz and amplitude of 1 mm
Using Mechanics of a Double Pendulum to Maximize Sport Performance
Sports have developed over time into an entire industry from the children who grow up playing sports to the professional players that fans love to watch. Because all sports involve movements of the human body, a bio-mechanical system, these movements may be modeled with mathematics and physics. Specifically, the sports of golf, tennis, and baseball can use the concepts of a double pendulum to maximize sport performance. The double pendulum model is applied to these sports by making the arm one pendulum and the club, racquet, or bat the second pendulum. A good understanding of the mechanics of a double pendulum and its connection to these sports can enhance the efforts of players and aid them in their performance
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