Domains of perfectionism: Prevalence and relationships with perfectionism, age, gender, and satisfaction with life

Perfectionists have been described as people who want to be perfect in all domains of their lives. Few studies to date, however, have investigated what domains people are perfectionistic in. Using two samples (109 university students, 289 Internet users), the present study investigated how being perfectionistic in 22 domains of life was related to perfectionism, age, gender, and satisfaction with life. Across samples, work and studies were the domains that most participants reported being perfectionistic in, followed by bodily hygiene, spelling, and presentation of documents. Whereas age, gender, and satisfaction with life showed significant relationships with selected domains of life, perfectionism showed significant positive correlations with the overall score (number of domains affected by perfectionism) and with being perfectionistic in individual domains. Further analyses showed that self-oriented perfectionism, rather than socially prescribed perfectionism, was responsible for these correlations. The findings indicate that, in most domains, being perfectionistic is internally motivated and not externally motivated. Moreover, they show that, while some perfectionists may be perfectionistic across domains, most perfectionists are perfectionistic only in selected domains

Output Feedback Invariants

The paper is concerned with the problem of determining a complete set of invariants for output feedback. Using tools from geometric invariant theory it is shown that there exists a quasi-projective variety whose points parameterize the output feedback orbits in a unique way. If the McMillan degree $n\geq mp$, the product of number of inputs and number of outputs, then it is shown that in the closure of every feedback orbit there is exactly one nondegenerate system.Comment: 15 page

Traveling Dark Solitons in Superfluid Fermi Gases

Families of dark solitons exist in superfluid Fermi gases. The energy-velocity dispersion and number of depleted particles completely determines the dynamics of dark solitons on a slowly-varying background density. For the unitary Fermi gas we determine these relations from general scaling arguments and conservation of local particle number. We find solitons to oscillate sinusoidally at the trap frequency reduced by a factor of $1/\sqrt{3}$. Numerical integration of the time-dependent Bogoliubov-de Gennes equation determines spatial profiles and soliton dispersion relations across the BEC-BCS crossover and proves consistent with the scaling relations at unitarity.Comment: Small changes in response to referee's comments; fig 1 revised and refs updated. Cross listed to nucl-th due to interest in the unitary Fermi ga

Time-crystalline behavior in an engineered spin chain ?

Time crystals appear when systems display a commensurate spontaneous breaking of the discrete time translational invariance imposed by an external periodic drive. No consensus on the definition has been reached as yet, but important aspects comprise robustness against small variations of the parameters and the initial quantum state. Often, disorder and interaction are thought to be essential ingredients for the occurrence of time crystals. We study a finite-length polarized XX spin chain engineered to display a spectrum of equidistant energy levels without drive and show that it keeps a spectrum of equidistant quasienergies in Floquet theory for a large variety of periodic driving schemes. This interesting behavior is explained by mapping the XX spin chain with $N+1$ sites to a single large spin with $S=N/2$ invoking the closure of the group SU(2). For suitably tuned parameters this system realizes time crystals of various periodicities for \emph{all} initial states. The robustness against variations of the parameters is also discussed. Thereby, we establish a clean system without interaction which can display the phenomenon of time crystallization.Comment: 17 pages, 5 figures. Title changed. Extended discussion of disorder effects. Accepted for publication in Phys. Rev.