Solution of the problem of catastrophic relaxation of homogeneous spin precession in superfluid 3^3He-B

The quantitative analysis of the "catastrophic relaxation" of the coherent spin precession in $^3$He-B is presented. This phenomenon has been observed below the temperature about 0.5 T$_c$ as an abrupt shortening of the induction signal decay. It is explained in terms of the decay instability of homogeneous transverse NMR mode into spin waves of the longitudinal NMR. Recently the cross interaction amplitude between the two modes has been calculated by Sourovtsev and Fomin \cite{SF} for the so-called Brinkman-Smith configuration, i.e. for the orientation of the orbital momentum of Cooper pairs along the magnetic field, ${\bf L}\parallel {\bf H}$. In their treatment, the interaction is caused by the anisotropy of the speed of the spin waves. We found that in the more general case of the non-parallel orientation of ${\bf L}$ corresponding to the typical conditions of experiment, the spin-orbital interaction provides the additional interaction between the modes. By analyzing experimental data we are able to distinguish which contribution is dominating in different regimes.Comment: 6 pages, 1 figure, submited to JETP letter

Quantum phase transitions in a new exactly solvable quantum spin biaxial model with multiple spin interactions

The new integrable quantum spin model is proposed. The model has a biaxial magnetic anisotropy of alternating coupling between spins together with multiple spin interactions. Our model gives the possibility to exactly find thermodynamic characteristics of the considered spin chain. The ground state of the model can reveal spontaneous values of the total magnetic and antiferromagnetic moments, caused by multiple spin couplings. Also, in the ground state, depending on the strength of multiple spin couplings, our model manifests several quantum critical points, some of which are governed by the external magnetic field

Phonons in magnon superfluid and symmetry breaking field

Recent experiments [1],[2] which measured the spectrum of the Goldstone collective mode of coherently precessing state in 3He-B are discussed using the presentation of the coherent spin precession in terms of the Bose-Einstein condensation of magnons. The mass in the spectrum of the Goldstone boson -- phonon in the superfluid magnon liquid -- is induced by the symmetry breaking field, which is played by the RF magnetic fieldComment: 2 pages, JETP Letters style, no figures, version accepted in JETP Letter

The Old Believers of Yekaterinburg: Number, Social Status, and Religious Identity

Поступила в редакцию 24.05.2017. Принята к печати 30.01.2018.Submitted on 24 May, 2017. Accepted on 30 January, 2018.В статье рассматривается влияние межрегиональных и локальных миграций на эволюцию городской старообрядческой общины на примере беглопоповского (с 1840-х гг. — часовенного) согласия Екатеринбурга в XVIII — начала XX в. Анализ численности и сословного состава по ревизиям, переписям и материалам учета естественного движения населения показывает последовательный, но неравномерный рост численности старообрядческого городского сообщества. Во время 3-й ревизии начала 1760-х гг. старообрядцев значилось около 1 тыс. человек (треть населения Екатеринбурга). В период веротерпимой политики 1780–1820-х гг. сформировались приходы Успенской и Н икольской часовен и к концу царствования Александра I в городе насчитывалось почти 1,5 тыс. староверов, большинство которых было записано в купеческое и мещанское сословия. Численность общин снизилась из-за «насаждения» единоверия в 1830–1850-е гг. и доля старообрядцев среди городского населения уменьшилась до нескольких процентов. Впоследствии количественный состав городского старообрядческого общества восстановился на фоне миграции крестьян в пореформенное время. Последнее обстоятельство повлияло на сословный состав прихожан, особенно молодежи, среди которой в нач. XX в. преобладали крестьяне. Наличие домовладений у большинства старообрядцев являлось благоприятным фактором для адаптации новых членов общины, не имевших собственного жилья. Картографирование элементов религиозного ландшафта, связанного с историей городских общин староверов беглопоповского (часовенного) согласия позволило локализовать их в пространстве Екатеринбурга XVIII – начала XX в. и выявить обособленность, связанную с устройством двух храмов (часовен), содержанием причта, предпочтениями внутриконфессиональных браков, наличием отдельного кладбища.This paper discusses the impact of regional and local migration on the Yekaterinburg Old Believer community with reference to Beglopopovtsy (or Chasovennye from the 1840s) between the 18th and early 20th centuries. The analysis of numbers and class composition carried out with reference to censuses and materials reflecting the population’s natural migration shows that the Old Believer community grew gradually though unevenly. During the 3rd census (Rus. ревизия) of the early 1760s, there were about one thousand Old Believers (one third of the population of Yekaterinburg). During the period of toleration between the 1780s and 1820s, the Assumption and St Nicholas Chapels were formed, and by the end of Alexander I’s reign, there were almost 1500 Old Believers most of whom were either merchants or petty bourgeois. The communities shrank due to the inculcation of Old Belief in the 1830s–1850s, leading to the number of Old Believers decreasing to only some percent. Later on, the number of the urban Old Believers grew again due to the migration of peasants during the post-reform time. The latter influenced the class composition of the parish, especially among youth with peasants making up the majority of them in the early 20th century. Most Old Believers owned accommodation which was a beneficial factor for the adaptation of the new members of the community who had no houses of their own. The cartographic visualisation of the religious landscape connected with the history of the urban Old Believer communities of the Beglopopovtsy (Chasovennye) helps localise them in the space of Yekaterinburg between the 18th and early 20th centuries and reveal the independence of the community with its two chapels, the structure of the parish and the clergy, its preference for same-religion marriages, and its own cemetery.Работа выполнена частично при финансовой поддержке РФФИ, грант № 15-06-08541 «Религиозное разнообразие евразийского города: статистический и картографический анализ (на примере Екатеринбурга в конце XIX — начале XXI в.)» (анализ статистики, подготовка карт) и за счет РНФ, проект 16-18-10105 «Этно-религиозная и демографическая динамика в горной Евразии в конце XIX — начале XX в. на примере Урала и Скандинавии» (анализ данных метрических книг).The work is partly sponsored by the Russian Foundation for Basic Research, Grant 15-06-08541 “The Religious Diversity of a Eurasian City: Statistical and Cartographic Analysis (with Reference to Yekaterinburg in the Late 19th — Early 21st Centuries)” (Statistical analysis of 18th — 19th centuries data about population, cartographic visualisation), and the Russian Science Foundation, Grant 16-18-10105 “Ethno-religious and Demographic Dynamics in Mountainous Eurasia around 1900. A Comparison of the Urals and Scandinavia” (1907–1918 church books analysis)

Stable Spin Precession at one Half of Equilibrium Magnetization in Superfluid 3He-B

New stable modes of spin precession have been observed in superfluid 3He-B. These dynamical order parameter states include precession with a magnetization S=pS_{eq} which is different from the equilibrium value S_{eq}. We have identified modes with p=1, 1/2 and \approx 0. The p=1/2 mode is the second member of phase correlated states of a spin superfluid. The new states can be excited in the temperature range 1-T/T_c \lesssim 0.02 where the energy barriers between the different local minima of the spin-orbit energy are small. They are stable in CW NMR due to low dissipation close to T_c.Comment: submitted to Physical Review Letters, 4 pages, revtex, 4 Figures in ftp://boojum.hut.fi/pub/publications/lowtemp/LTL-96005.p

Magnon BEC in superfluid 3He-A

The new mode of magnetization precession in superfluid 3He-A in a squeezed aerogel has been recently reported. We consider this mode in terms of the Bose-Einstein condensation (BEC) of magnons. The difference between magnon BEC states in 3He-A and in 3He-B is discussed.Comment: 6 pages, 2 figures, JETP Letters style, published versio

Observation of Coherent Precession of Magnetization in Superfluid 3He A-phase

We report the first observation of coherent quantum precession of magnetization (CQP) in superfluid 3He-A in aerogel. The coherent precession in bulk 3He A-phase is unstable due to the positive feedback of spin supercurrent to the gradient of phase of precession. It was predicted that the homogeneous precession will be stable if the orbital momentum of 3He-A could be oriented along the magnetic field. We have succeeded to prepare this configuration by emerging 3He in uniaxially-deformed anisotropic aerogel. The dissipation rate of coherent precession states in aerogel is much larger then one in bulk 3He-B. We propose a mechanism of this dissipation.Comment: 4 pages, 4 figure