7 research outputs found
Magnetic Field Induced Quantum Criticality via new Asymptotically AdS_5 Solutions
Using analytical methods, we derive and extend previously obtained numerical
results on the low temperature properties of holographic duals to
four-dimensional gauge theories at finite density in a nonzero magnetic field.
We find a new asymptotically AdS_5 solution representing the system at zero
temperature. This solution has vanishing entropy density, and the charge
density in the bulk is carried entirely by fluxes. The dimensionless magnetic
field to charge density ratio for these solutions is bounded from below, with a
quantum critical point appearing at the lower bound. Using matched asymptotic
expansions, we extract the low temperature thermodynamics of the system. Above
the critical magnetic field, the low temperature entropy density takes a simple
form, linear in the temperature, and with a specific heat coefficient diverging
at the critical point. At the critical magnetic field, we derive the scaling
law s ~ T^{1/3} inferred previously from numerical analysis. We also compute
the full scaling function describing the region near the critical point, and
identify the dynamical critical exponent: z=3.
These solutions are expected to holographically represent boundary theories
in which strongly interacting fermions are filling up a Fermi sea. They are
fully top-down constructions in which both the bulk and boundary theories have
well known embeddings in string theory.Comment: 50 page
The Baryonic Phase in Holographic Descriptions of the QCD Phase Diagram
We study holographic models of the QCD temperature-chemical potential phase
diagram based on the D3/D7 system with chiral symmetry breaking. The baryonic
phase may be included through linked D5-D7 systems. In a previous analysis of a
model with a running gauge coupling a baryonic phase was shown to exist to
arbitrarily large chemical potential. Here we explore this phase in a more
generic phenomenological setting with a step function dilaton profile. The
change in dilaton generates a linear confining potential and opposes
the screening effect of temperature. We show that the persistence of the
baryonic phase depends on the step size and that QCD-like phase diagrams can be
described. The baryonic phase's existence is qualitatively linked to the
existence of confinement in Wilson loop computations in the background.Comment: 21 pages, 7 figure
Towards a Holographic Model of the QCD Phase Diagram
We describe the temperature-chemical potential phase diagrams of holographic
models of a range of strongly coupled gauge theories that display chiral
symmetry breaking/restoration transitions. The models are based on the
D3/probe-D7 system but with a phenomenologically chosen running
coupling/dilaton profile. We realize chiral phase transitions with either
temperature or density that are first or second order by changing the dilaton
profile. Although the models are only caricatures of QCD they show that
holographic models can capture many aspects of the QCD phase diagram and hint
at the dependence on the running coupling.Comment: 11 pages, 9 figures, v2: minor corrections, Invited contribution to
an AdS/CFT edition of Journal of Physics
The addition of the immunomodulator mifamurtide to adjuvant chemotherapy for early osteosarcoma: a retrospective analysis
Background. Current treatment recommendations for high grade non-metastatic osteosarcoma include perioperative chemotherapy and surgery. Despite this intensive protocol, approximately 40% of patients will relapse. The addition of the immunomodulator mifamurtide to adjuvant cytotoxic chemotherapy was associated with a significant improvement in 6-year overall survival (OS) in young patients with resectable osteosarcoma, leading to its approval in Europe and other countries. Very limited real-world data are reported on its use. Methods. We retrospectively evaluated data from osteosarcoma patients who received mifamurtide in the adjuvant setting. Data were obtained from medical records in 2 high-volume bone sarcoma centers. The aim of this study was to collect real-world data on mifamurtide safety and efficacy in Greece. Results. We identified 15 patients with completely resected osteosarcoma who received mifamurtide from September 2015 to January 2020. Median age at diagnosis was 24 years old (16–76). Osteosarcoma arose in the lower extremities (n = 12), in the upper extremities (n = 2) or in the ilium (n = 1). The majority of patients (n = 13) received cisplatin/doxorubicin/methotrexate as perioperative chemotherapy and the remaining patients cisplatin/doxorubicin. After a median follow-up of 46.9 months (range, 32.8–61.1), the median recurrence-free survival was 58.7 months (range, 18.5–98.8) and the median OS 64.1 months (range, 25.6–102.6). Except for fever and chills, the only adverse event probably related to mifamurtide was pericarditis (n = 1). Conclusions. Mifamurtide was well tolerated in a Greek osteosarcoma population, including patients older than 30 years. The small sample size and the non-comparative design do not allow drawing conclusions on the drug benefit in terms of survival. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature