23 research outputs found
Asymptotically Schroedinger Space-Times: TsT Transformations and Thermodynamics
We study the complete class of 5-dimensional asymptotically Schroedinger
space-times that can be obtained as the TsT transform of a 5-dimensional
asymptotically AdS space-time. Based on this we identify a conformal class of
Schroedinger boundaries. We use a Fefferman-Graham type expansion to study the
on-shell action for this class of asymptotically Schroedinger space-times and
we show that its value is TsT invariant. In the second part we focus on black
hole space-times and prove that black hole thermodynamics is also TsT
invariant. We use this knowledge to argue that thermal global Schroedinger
space-time at finite chemical potential undergoes a Hawking-Page type phase
transition.Comment: References adde
Particle Number and 3D Schroedinger Holography
We define a class of space-times that we call asymptotically locally
Schroedinger space-times. We consider these space-times in 3 dimensions, in
which case they are also known as null warped AdS. The boundary conditions are
formulated in terms of a specific frame field decomposition of the metric which
contains two parts: an asymptotically locally AdS metric and a product of a
lightlike frame field with itself. Asymptotically we say that the lightlike
frame field is proportional to the particle number generator N regardless of
whether N is an asymptotic Killing vector or not.
We consider 3-dimensional AlSch space-times that are solutions of the massive
vector model. We show that there is no universal Fefferman-Graham (FG) type
expansion for the most general solution to the equations of motion. We show
that this is intimately connected with the special role played by particle
number. Fefferman-Graham type expansions are recovered if we supplement the
equations of motion with suitably chosen constraints. We consider three
examples. 1). The massive vector field is null everywhere. The solution in this
case is exact as the FG series terminates and has N as a null Killing vector.
2). N is a Killing vector (but not necessarily null). 3). N is null everywhere
(but not necessarily Killing). The latter case contains the first examples of
solutions that break particle number, either on the boundary directly or only
in the bulk. Finally, we comment on the implications for the problem of
holographic renormalization for asymptotically locally Schroedinger
space-times.Comment: 56 pages, v3: matches version published in JHE
Torsional Newton-Cartan Geometry and Lifshitz Holography
We obtain the Lifshitz UV completion in a specific model for z=2 Lifshitz
geometries. We use a vielbein formalism which enables identification of all the
sources as leading components of well-chosen bulk fields. We show that the
geometry induced from the bulk onto the boundary is a novel extension of
Newton-Cartan geometry with a specific torsion tensor. We explicitly compute
all the vevs including the boundary stress-energy tensor and their Ward
identities. After using local symmetries/Ward identities the system exhibits
6+6 sources and vevs. The FG expansion exhibits, however, an additional free
function which is related to an irrelevant operator whose source has been
turned off. We show that this is related to a second UV completion.Comment: v2: 5 pages, matches version published in PR
Home care—a safe and attractive alternative to inpatient administration of intensive chemotherapies
Objective: The objective of this study was to evaluate feasibility, safety, perception, and costs of home care for the administration of intensive chemotherapies. Methods: Patients receiving sequential chemotherapy in an inpatient setting, living within 30km of the hospital, and having a relative to care for them were offered home care treatment. Chemotherapy was administered by a portable, programmable pump via an implantable catheter. The main endpoints were safety, patient's quality of life [Functional Living Index—Cancer (FLIC)], satisfaction of patients and relatives, and costs. Results: Two hundred days of home care were analysed, representing a total of 46 treatment cycles of intensive chemotherapy in 17 patients. Two cycles were complicated by technical problems that required hospitalisation for a total of 5days. Three major medical complications (heart failure, angina pectoris, and major allergic reaction) could be managed at home. Grades 1 and 2 nausea and vomiting occurring in 36% of patients could be treated at home. FLIC scores remained constant throughout the study. All patients rated home care as very satisfactory or satisfactory. Patient benefits of home care included increased comfort and freedom. Relatives acknowledged better tolerance and less asthenia of the patient. Home care resulted in a 53% cost benefit compared to hospital treatment (€420 ± 120/day vs. €896 ± 165/day). Conclusion: Administration of intensive chemotherapy regimens at home was feasible and safe. Quality of life was not affected; satisfaction of patients and relatives was very high. A psychosocial benefit was observed for patients and relatives. Furthermore, a cost-benefit of home care compared to hospital treatment was demonstrate
Brown-York Energy and Radial Geodesics
We compare the Brown-York (BY) and the standard Misner-Sharp (MS) quasilocal
energies for round spheres in spherically symmetric space-times from the point
of view of radial geodesics. In particular, we show that the relation between
the BY and MS energies is precisely analogous to that between the
(relativistic) energy E of a geodesic and the effective (Newtonian) energy
E_{eff} appearing in the geodesic equation, thus shedding some light on the
relation between the two. Moreover, for Schwarzschild-like metrics we establish
a general relationship between the BY energy and the geodesic effective
potential which explains and generalises the recently observed connection
between negative BY energy and the repulsive behaviour of geodesics in the
Reissner-Nordstrom metric. We also comment on the extension of this connection
between geodesics and the quasilocal BY energy to regions inside a horizon.Comment: v3: 7 pages, shortened and revised version to appear in CQ
Holographic Renormalization for z=2 Lifshitz Space-Times from AdS
Lifshitz space-times with critical exponent z=2 can be obtained by
dimensional reduction of Schroedinger space-times with critical exponent z=0.
The latter space-times are asymptotically AdS solutions of AdS gravity coupled
to an axion-dilaton system and can be uplifted to solutions of type IIB
supergravity. This basic observation is used to perform holographic
renormalization for 4-dimensional asymptotically z=2 locally Lifshitz
space-times by Scherk-Schwarz dimensional reduction of the corresponding
problem of holographic renormalization for 5-dimensional asymptotically locally
AdS space-times coupled to an axion-dilaton system. We can thus define and
characterize a 4-dimensional asymptotically locally z=2 Lifshitz space-time in
terms of 5-dimensional AdS boundary data. In this setup the 4-dimensional
structure of the Fefferman-Graham expansion and the structure of the
counterterm action, including the scale anomaly, will be discussed. We find
that for asymptotically locally z=2 Lifshitz space-times obtained in this way
there are two anomalies each with their own associated nonzero central charge.
Both anomalies follow from the Scherk--Schwarz dimensional reduction of the
5-dimensional conformal anomaly of AdS gravity coupled to an axion-dilaton
system. Together they make up an action that is of the Horava-Lifshitz type
with nonzero potential term for z=2 conformal gravity.Comment: 32 pages, v2: modified discussion of the central charge
Geometry of Schroedinger Space-Times, Global Coordinates, and Harmonic Trapping
We study various geometrical aspects of Schroedinger space-times with
dynamical exponent z>1 and compare them with the properties of AdS (z=1). The
Schroedinger metrics are singular for 1<z<2 while the usual Poincare
coordinates are incomplete for z \geq 2. For z=2 we obtain a global coordinate
system and we explain the relations among its geodesic completeness, the choice
of global time, and the harmonic trapping of non-relativistic CFTs. For z>2, we
show that the Schroedinger space-times admit no global timelike Killing
vectors.Comment: 15 pages, v2: some comments and references adde
Geometry of Schroedinger Space-Times II: Particle and Field Probes of the Causal Structure
We continue our study of the global properties of the z=2 Schroedinger
space-time. In particular, we provide a codimension 2 isometric embedding which
naturally gives rise to the previously introduced global coordinates.
Furthermore, we study the causal structure by probing the space-time with point
particles as well as with scalar fields. We show that, even though there is no
global time function in the technical sense (Schroedinger space-time being
non-distinguishing), the time coordinate of the global Schroedinger coordinate
system is, in a precise way, the closest one can get to having such a time
function. In spite of this and the corresponding strongly Galilean and almost
pathological causal structure of this space-time, it is nevertheless possible
to define a Hilbert space of normalisable scalar modes with a well-defined
time-evolution. We also discuss how the Galilean causal structure is reflected
and encoded in the scalar Wightman functions and the bulk-to-bulk propagator.Comment: 32 page