15,320 research outputs found
One loop renormalization for the axial Ward-Takahashi identity in Domain-wall QCD
We calculate one-loop correction to the axial Ward-Takahashi identity given
by Furman and Shamir in domain-wall QCD. It is shown perturbatively that the
renormalized axial Ward-Takahashi identity is satisfied without fine tuning and
the ``conserved'' axial current receives no renormalization, giving .
This fact will simplify the calculation of the pion decay constant in numerical
simulations since the decay constant defined by this current needs no lattice
renormalization factor.Comment: 16 pages, 3 axodraw.sty figure
Spontaneous Parity Violation in QCD At Finite Temperature: On the Inapplicability of the Vafa-Witten Theorem
The generalization of the Vafa-Witten theorem ruling out parity violation to
QCD at finite temperature is considered. It is shown that this generalization
of the theorem rules out Lorentz-invariant parity violating operators from
spontaneously acquiring vacuum expectation values. However, it does not rule
out Lorentz-noninvariant parity-violating operators from acquiring expectation
values. Other situations where the theorem is inapplicable are also discussed.Comment: Minor typos correcte
A fully-integrated 1.8-V, 2.8-W, 1.9-GHz, CMOS power amplifier
This paper demonstrated the first 2-stage, 2.8W, 1.8V, 1.9GHz fully-integrated DAT power amplifier with 50Ω input and output matching using 0.18Όm CMOS transistors. It has a small-signal gain of 27dB. The amplifier provides 2.8W of power into a 50Ω load with a PAE of 50%
Chiral perturbation theory in a theta vacuum
We consider chiral perturbation theory (ChPT) with a non-zero theta term. Due
to the CP violating term, the vacuum of chiral fields is shifted to a
non-trivial element on the SU(N_f) group manifold. The CP violation also
provides mixing of different CP eigenstates, between scalar and pseudoscalar,
or vector and axialvector operators. We investigate upto O(theta^2) effects on
the mesonic two point correlators of ChPT to the one-loop order. We also
address the effects of fixing topology, by using saddle point integration in
the Fourier transform with respect to theta.Comment: 31 pages, references added, minor corrections, version published in
PR
A 2.4-GHz, 2.2-W, 2-V fully-integrated CMOS circular-geometry active-transformer power amplifier
A 2.4-GHz, 2.2-W, 2-V fully integrated circular geometry power amplifier with 50 Ω input and output matching is fabricated using 2.5V, 0.35 pm CMOS transistors. It can also produce 450mW using a 1V supply. Harmonic suppression is 64dB or better. An on-chip circular-geometry active-transformer is used to combine several push-pull low-voltage amplifiers efficiently to produce a larger output power while maintaining a 50 Ω match. This new on-chip power combining and impedance matching method uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any off-chip component such as wirebonds. It also desensitizes the operation of the amplifier to the inductance of bonding wires and makes the design more reproducible. This new topology makes possible a fully-integrated 2.2W, 2.4GHz, low voltage CMOS power amplifier for the first time
Green's Function for Nonlocal Potentials
The single-particle nuclear potential is intrinsically nonlocal. In this
paper, we consider nonlocalities which arise from the many-body and fermionic
nature of the nucleus. We investigate the effects of nonlocality in the nuclear
potential by developing the Green's function for nonlocal potentials. The
formal Green's function integral is solved analytically in two different limits
of the wavelength as compared to the scale of nonlocality. Both results are
studied in a quasi-free limit. The results illuminate some of the basic effects
of nonlocality in the nuclear medium.Comment: Accepted for publication in J. Phys.
The Class-E/F Family of ZVS Switching Amplifiers
A new family of switching amplifiers, each member having some of the features of both class E and inverse F, is introduced. These class-E/F amplifiers have class-E features such as incorporation of the transistor parasitic capacitance into the circuit, exact truly switching time-domain solutions, and allowance for zero-voltage-switching operation. Additionally, some number of harmonics may be tuned in the fashion of inverse class F in order to achieve more desirable voltage and current waveforms for improved performance. Operational waveforms for several implementations are presented, and efficiency estimates are compared to class-E
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