We calculate the bubble nucleation rate in a fourth-order gravity theory whose action contains an R term, under the thin-wall approximation, by two different methods. First the bounce solution is found for the Euclidean version of the original action. Next, we use a conformal transformation to transform the theory into general relativity with an additional scalar field and then proceed to find ...

We determine the fermionic corrections to the nucleation rate of bubbles at the electroweak phase transition. The fermion determinant is evaluated exactly and by using the gradient expansion. The gradient expansion is found to be a reliable approximation and is used to extrapolate to the large values of νn = (2n+ 1)πT needed in the Matsubara sum. The contribution to effective action is found to...

Bubble formation and growth on a water-splitting semiconductor photoelectrode under illumination with above-bandgap radiation provide a direct measurement of the gas-evolving reaction rate. Optical microscopy was used to record the bubble growth on single-crystal strontium titanate immersed in basic aqueous electrolyte and illuminated with UV light at 351/364 nm from a focused argon laser. By a...

We present a consistent picture of tunnelling in field theory. Our results apply both to high-temperature field theories in four dimensions and to zero-temperature threedimensional ones. Our approach is based on the notion of a coarse-grained potential Uk that incorporates the effect of fluctuations with characteristic momenta above a given scale k. Uk is non-convex and becomes equal to the con...

We develop a method to calculate the prefactor in the expression for the bubble nucleation rate. A fermion with Yukawa coupling is considered where a step potential can be used as a good approximation in the thin wall limit. Corrections due to thicker walls are considered by perturbing about the thin wall case. We derive the thermal one loop effective action, calculating it numerically and find...

An experimental study of saturated pool boiling from a single artificial nucleation site on a polished copper surface has been performed. Isolated bubbles grow and depart from the artificial cavity and the bubble dynamics are recorded with a high speed camera. Experimental results are obtained for bubble growth, departure and vertical rise both with and without the application of an electric fi...

Heterogeneous bubble nucleation at surfaces has been notorious because of its irreproducibility. Here controlled multibubble surface cavitation is achieved by using a hydrophobic surface patterned with microcavities. The expansion of the nuclei in the microcavities is triggered by a fast lowering of the liquid pressure. The procedure allows us to control and fix the bubble distance within the b...

We study the formation of vortices in a U(1) gauge theory following a firstorder transition proceeding by bubble nucleation, in particular the effect of a low velocity of expansion of the bubble walls. To do this, we use a twodimensional model in which bubbles are nucleated at random points in a plane and at random times and then expand at some velocity vb < c. Within each bubble, the phase ang...

The behavior of fields during weak first order phase transitions has been a source of great interest. Several studies have shown either a need for changes to the current theory of thermal phase transitions or the inclusion of carefully calculated corollaries to the present models [1–3]. Sub-critical bubbles and oscillon solutions may give rise to phase mixing in which these fluctuations in the ...

New data are reported from the operation of a 4.0 kg CF3I bubble chamber in the 6800 foot deep SNOLAB underground laboratory. The effectiveness of ultrasound analysis in discriminating alpha decay background events from single nuclear recoils has been confirmed, with a lower bound of >99.3% rejection of alpha decay events. Twenty single nuclear recoil event candidates and three multiple bubble ...