185 research outputs found
Explosive Collisions at RHIC?
Motivated by experimental results from RHIC, we suggest how a condensate for
the Polyakov loop might produce explosive behavior at the QCD phase transition.
This is due to a rapid rollover of the condensate field below the transition
temperature
Effective potential for SU(2) Polyakov loops and Wilson loop eigenvalues
We simulate SU(2) gauge theory at temperatures ranging from slightly below
to roughly for two different values of the gauge coupling. Using a
histogram method, we extract the effective potential for the Polyakov loop and
for the phases of the eigenvalues of the thermal Wilson loop, in both the
fundamental and adjoint representations. We show that the classical potential
of the fundamental loop can be parametrized within a simple model which
includes a Vandermonde potential and terms linear and quadratic in the Polyakov
loop. We discuss how parametrizations for the other cases can be obtained from
this model.Comment: 16 pages, 39 figure
Is the ridge formed by aligned jet propagation and medium flow?
Motivated by the recent observation that the ridge decreases with trigger
particle angle () relative to the event plane, it is theorized that the
ridge is formed by interplay between jet propagation and medium flow. Such
interplay may produce asymmetry in the ridge azimuthal correlation at a fixed
. We present an analysis of this asymmetry from STAR data. We found an
asymmetric ridge with maximum asymmetry at concurrent
with a symmetric jet at all .Comment: 2 pages, 2 figures, Quark Matter 200
Note on counterterms in asymptotically flat spacetimes
We consider in more detail the covariant counterterm proposed by Mann and
Marolf in asymptotically flat spacetimes. With an eye to specific practical
computations using this counterterm, we present explicit expressions in general
dimensions that can be used in the so-called `cylindrical cut-off' to
compute the action and the associated conserved quantities for an
asymptotically flat spacetime. As applications, we show how to compute the
action and the conserved quantities for the NUT-charged spacetime and for the
Kerr black hole in four dimensions.Comment: 13 pages, v. 2 added reference
On Borrowed Time -- Preventing Static Power Side-Channel Analysis
In recent years, static power side-channel analysis attacks have emerged as a
serious threat to cryptographic implementations, overcoming state-of-the-art
countermeasures against side-channel attacks. The continued down-scaling of
semiconductor process technology, which results in an increase of the relative
weight of static power in the total power budget of circuits, will only improve
the viability of static power side-channel analysis attacks. Yet, despite the
threat posed, limited work has been invested into mitigating this class of
attack. In this work we address this gap. We observe that static power
side-channel analysis relies on stopping the target circuit's clock over a
prolonged period, during which the circuit holds secret information in its
registers. We propose Borrowed Time, a countermeasure that hinders an
attacker's ability to leverage such clock control. Borrowed Time detects a
stopped clock and triggers a reset that wipes any registers containing
sensitive intermediates, whose leakages would otherwise be exploitable. We
demonstrate the effectiveness of our countermeasure by performing practical
Correlation Power Analysis attacks under optimal conditions against an AES
implementation on an FPGA target with and without our countermeasure in place.
In the unprotected case, we can recover the entire secret key using traces from
1,500 encryptions. Under the same conditions, the protected implementation
successfully prevents key recovery even with traces from 1,000,000 encryptions
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