Bose-Einstein condensates (BECs) represent one of the very few manifestations of purely quantum effects on a macroscopic level [1,2]. The vast majority of BECs achieved in the lab to date consist of bosonic atoms, which macroscopically populate the ground state once a threshold temperature has been reached [3]. Recently, a new type of condensate was observed -the photon BEC [4], where light in a dye-filled cavity thermalises with dye molecules under the influence of an external driving laser, condensing to the lowest-energy mode. However, the precise relationship between the photon BEC and symmetry-breaking phenomena has not yet been investigated. Here we consider mediuminduced symmetry breaking in a photon BEC and show that it can be used as a quantum sensor. The introduction of polarisable objects such as chiral molecules lifts the degeneracy between cavity modes of different polarisations. Even a tiny imbalance is imprinted on the condensate polarisation in a 'winner takes it all' effect. When used as a sensor for enantiomeric excess, the predicted sensitivity exceeds that of contemporary methods based on circular dichroism. Our results introduce a new symmetry-breaking mechanism that is independent of the external pump, and demonstrate that the photon BEC can be used for practical purposes.The pursuit of Bose-Einstein condensates (BECs) has led to continuing innovation across theory and experiment since its first prediction in 1924 [1,2] and experimental observation in 1995 [3]. A remarkable recent development has been the photon BEC, whose first realisation in 2010 [4] brought about a flourishing field of modern research (e.g. [5][6][7][8][9][10]). The condensate of light consists of a macroscopically occupied lowest-energy state of a photon field confined to a cavity, resulting in a central bright spot in the cavity's emission pattern.In order to obtain a condensate of light, three conditions must be satisfied. The first of these is that photons should be allowed to exchange energy with each other in a photon-number conserving way. As indicated in Fig. 1, this is achieved by filling a cavity with a dye whose emission and absorption spectra fulfil the Kennard-Stepanov relation [11,12], which allows an effective thermal interaction between the photons via repeated absorption and re-emission. The second is that an effective photon mass should be provided in order to sustain the analogy with atomic condensates, this is given by the curvature of the cavity mirrors which causes the photon dispersion relation to be equivalent to that of massive bosons. Finally, a confining potential is needed-this is naturally provided by the cavity. The resulting system is similar to a laser, one crucial difference being that as the pump power is increased there is a sharp jump in the occu-1 arXiv:1905.07590v1 [quant-ph] 18 May 2019 Chiral molecules to be studied Rhodamine 6G dye r R Laser Polarimeter Figure 1: Schematic of the physical system considered here.pation number of the lowest mode, occurring at far below the power requ...

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After hydraulic fracturing treatment, wellbore clean-out takes significant amount of time, and therefore, the commissioning of the well is delayed. In addition to production losses, production companies CAPEX and OPEX are also increasing proportionally to frac fleet activity. As a common practice, in western Siberia fracturing treatment is underflushed by about 0.5 cubic meters. This is supposed to prevent unintentional overflush and, as a result, hydraulic fracture closure at the wellbore. The loss of contact between the propped fracture and the perforated section of the well can neutralize the effect of hydraulic fracturing. This can happen in the first days of production after the operation or in a long-term perspective. On the other hand, overflush during hydraulic fracturing is common practice for unconventional formations. It allows to use various well completion technologies with the cemented liners and significantly reduces time required to complete multistage fracturing treatment. The objective of this paper is to show the approach and experience of the company "Salym petroleum development" (SPD). Positive result was obtained with proppant slurry overflush operation during treatment of conventional reservoirs.

Various methods for limiting the plasma volume made it possible to produce the continuous point-like high-temperature terahertz discharge at the Novosibirsk free-electron laser (NovoFEL). When a krypton-nitrogen jet was injected into the focus of the NovoFEL radiation, as compressed as possible and having an average power of about 200 W, a spherical plasma with diameter of 1 mm, temperature of 4-4.5 eV (46000-52000 K°), and density of 3.5 × 1017 cm-3 was obtained. The ion composition of the plasma was represented mainly by triply and doubly ionized krypton atoms (Kr IV and Kr III). The absolute stability of the plasma, which tends to self-oscillate, was achieved through the use of a special negative optical feedback.

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