Hamiltonian light-front dynamics of quantum fields may provide a useful approach to systematic non-perturbative approximations to quantum field theories. We investigate inequivalent Hilbert-space representations of the light-front field algebra in which the stability group of the light-front is implemented by unitary transformations. The Hilbert space representation of states is generated by th...

We suggest a constrained instanton (CI) solution in the physical QCD vacuum which is described by large-scale vacuum field fluctuations. This solution decays exponentially at large distances. It is stable only if the interaction of the instanton with the background vacuum field is small and additional constraints are introduced. The CI solution is explicitly constructed in the ansatz form, and ...

A method constructing vacuum servo control system with a combined vacuum generator is proposed and the single neural adaptive PID control strategy is also proposed due to the inherent defects of the vacuum servo system in this paper. The influence of the system parameters to the characteristics of the vacuum servo system is analyzed and discussed. The simulation and the experiment show that the...

We study the dynamics of false vacuum bubbles in the Brans-Dicke theory of gravity by using the thin shell or thin wall approximation. We consider a false vacuum bubble that has a different value for the Brans-Dicke field between the inside false vacuum region and the outside true vacuum region. Within a certain limit of field values, the difference of field values makes the effective tension o...

It is well known that the complex structure of the QCD vacuum can, in some regimes, be parametrized by local vacuum condensates, i.e. the expectation values of operators where all the perturbative vacuum fluctuations are taken out at the best of our ability . The first attempt to calculate the effect of non-perturbative vacuum condensates on the energy levels of heavy quarkonia was performed in...

Measurements with low Z targets at internal experiments typically imply a gas load which deteriorates the ring vacuum. Future experiments need reliable estimates for the expected vacuum conditions in order to design 4π detectors closely surrounding the interaction area. We present a method for the calculation of the resulting vacuum of such a complex system using a Pellet Target. In order to te...

Using a variable frequency drive (VFD) in order to drive the vacuum pump of a milking machine allows a dramatic reduction in energy use, while still producing equivalent vacuum stability. The VFD technology is able to adjust the rate of air removal from the milking system by changing the speed of the vacuum pump motor. A PID controller was developed in order to command the electric motor drivin...

When women in the second stage of labor fail to progress to a spontaneous delivery, vacuum extractors have been used to successfully aid delivery. Data from the U.S. Department of Health and Human Services’ National Center for Health Statistics revealed that vacuum-assisted deliveries accounted for approximately 5% of all deliveries in 2004, based on a seven-state sample of the expanded health ...

When it switches on in 2008, the 26.7 km Large Hadron Collider (LHC) at CERN, will have the world's largest vacuum system operating over a wide range of pressures and employing an impressive array of vacuum technologies. This system is composed by 54 km of UHV vacuum for the circulating beams and 50 km of insulation vacuum around the cryogenic magnets and the liquid helium transfer lines. Over ...