Related papers: Long-range order in the A-like phase of superfluid…
Within a phenomenological approach possible forms of the order parameter of the superfluid phases of 3He in a vicinity of the transition temperature are discussed. Effect of aerogel is described by a random tensor field interacting with the…
As a consequence of a continuous degeneracy of the order parameter of the superfluid 3He the quenched disorder in a form of aerogel gives rise both to a disruption of the orientational long-range order of the condensate and to a significant…
Deformed aerogels induce a global anisotropy in the superfluid 3He and orient the orbital part of its order parameter. Here a phenomenological theory of the orientational effect of elastic deformations of aerogels on the superfluid phases…
The orbital anisotropy induced in the superfluid 3He by nematic aerogel is, generally speaking, spatially non-uniform. This anisotropy in its turn induces spatial fluctuations of the order parameter. It is shown here that for the polar…
Spacial variation of the orbital part of the order parameter of $^3$He-A in aerogel is represented as a random walk of the unit vector $\mathbf{l}$ in a field of random anisotropy produced by the strands of aerogel. For a range of…
Highly anisotropic "nematically ordered" aerogel induces global uniaxial anisotropy in superfluid 3He. The anisotropy lowers symmetry of 3He in aerogel from spherical to axial. As a result instead of one transition temperature in the state,…
We report on orientation of the order parameter in the 3He-A and 3He-B phases caused by aerogel anisotropy. In 3He-A we have observed relatively homogeneous NMR line with an anomalously large negative frequency shift. We can attribute this…
Deformation of aerogel strongly modifies the orientation of the order parameter of superfluid 3He confined in aerogel. We used a radial squeezing of aerogel to keep the orbital angular momentum of the 3He Cooper pairs in the plane…
It was found that NMR properties of both superfluid phases of $^3$He in anisotropic aerogel can be described in terms of the bulk superfluid order parameters with the orbital order parameter vector fixed by anisotropy of the aerogel sample.…
Random textures of the orbital part of the order parameter of superfluid 3He-A in aerogel are analyzed theoretically in the Ginzburg and Landau region both in the presence and in the absence of a global anisotropy. Correlation functions of…
Interpretation of the recent experiments of V.V. Dmitriev et. al. on longitudinal resonance in the A-like phase, based on specific properties of "robust" order parameter is proposed.
Stimulated by the results of NMR experiments with superfluid $^3$He in "nematically ordered" aerogel [1] we report on the results of phenomenological analysis of stability of different phases of superfluid $^3$He subjected to a strong…
Stable pairing states of superfluid 3He in aerogel are examined in the case with a global uniaxial anisotropy which may be created by applying an uniaxial stress to the aerogel. Due to such a global anisotropy, the stability region of an…
It is established theoretically that an ordered state with continuous symmetry is inherently unstable to arbitrarily small amounts of disorder [1, 2]. This principle is of central importance in a wide variety of condensed systems including…
Superfluid 3He-A shares the properties of spin nematic and chiral orbital ferromagnet. Its order parameter is characterized by two vectors d and l. This doubly anisotropic superfluid, when it is confined in aerogel, represents the most…
Phenomenological criterion of a choice of the order parameter for superfluid phases of $^3$He in aerogel in a near vicinity of the transition temperature is formulated. Except for the B-phase this criterion is met by the order parameter of…
Effect of uniaxially-deformed aerogel on orientation of the order parameter of superfluid $^3He$ is considered. Approach used takes into account correlations in positions of particles forming aerogel. Calculations show that for the case of…
Within a phenomenological approach a criterion for a choice of forms of the order parameter of the superfluid phases of 3He in aerogel in a vicinity of the transition temperature is derived. The order parameter of bulk B-phase of 3He meets…
Recent theoretical and experimental studies of superfluid $^3$He in aerogels with a global anisotropy, e.g., due to an external stress, have definitely shown that the A-like phase with an equal spin pairing (ESP) in such aerogel samples is…
It has been suggested that anisotropic quasiparticle scattering will stabilize anisotropic phases of superfluid $^3$He contained within highly porous silica aerogel. For example, global anisotropy introduced via uniaxial compression of…