367 research outputs found
Relaxation dynamics of an isolated large-spin Fermi gas far from equilibrium
A fundamental question in many-body physics is how closed quantum systems
reach equilibrium. We address this question experimentally and theoretically in
an ultracold large-spin Fermi gas where we find a complex interplay between
internal and motional degrees of freedom. The fermions are initially prepared
far from equilibrium with only a few spin states occupied. The subsequent
dynamics leading to redistribution among all spin states is observed
experimentally and simulated theoretically using a kinetic Boltzmann equation
with full spin coherence. The latter is derived microscopically and provides
good agreement with experimental data without any free parameters. We identify
several collisional processes, which occur on different time scales. By varying
density and magnetic field, we control the relaxation dynamics and are able to
continuously tune the character of a subset of spin states from an open to a
closed system.Comment: 18 pages, 9 figure
Engineering spin waves in a high-spin ultracold Fermi gas
We report on the detailed study of multi-component spin-waves in an s=3/2
Fermi gas where the high spin leads to novel tensorial degrees of freedom
compared to s = 1/2 systems. The excitations of a spin-nematic state are
investigated from the linear to the nonlinear regime, where the tensorial
character is particularly pronounced. By tuning the initial state we engineer
the tensorial spin-wave character, such that the magnitude and sign of the
counterflow spin-currents are effectively controlled. A comparison of our data
with numerical and analytical results shows excellent agreement.Comment: 9 pages, 4 figure
Recommended from our members
Updated April 26, 2002
This report provides an overview of the 2002 farm bill and an update status of the farm bill
Recommended from our members
Farm Economic Relief: Issues and Options for Congress
This report discusses issues regarding Agriculture funding and subsidies. In response to low prices, natural disasters,
and other farm-related problems, Congress
has, over 3 successive years, provided a
total of about 7.113
billion for additional farm income and related
assistance, of which $5.5 billion is to be spent
in FY2000
Recommended from our members
Updated March 13, 2002
This report provides an overview of the 2002 farm bill and an update status of the farm bill
Recommended from our members
Farm "Counter-Cyclical Assistance"
This report discusses the reauthorization of major farm income and commodity
price support programs that expire after crop year 2002. Many agricultural interests
expect that a new “counter-cyclical assistance” program will be an integral component
of future farm policy. The intent of counter-cyclical assistance is to provide more
government support when farm prices and/or incomes decline, and less support when
they improve
Recommended from our members
The 2002 Farm Bill: Overview and Status
This report discusses the provisions of the 1996 farm bill, which was due to expire in 2002 but was extended (P.L. 107-171) for an additional 6 years on May 13, 2002
Recommended from our members
The 2002 Farm Bill: Overview and Status
The Federal Agriculture Improvement and Reform, or FAIR, Act of 1996 (commonly known as the "farm bill"), which was due to expire in 2002, is expected to be extended for another six years when President Bush signs the bill into law. This report discusses the provisions of the new "farm bill," including the federal spending involved
Recommended from our members
106th Congress
This report discusses issues regarding Agriculture funding, specifically the Federal Agriculture Improvement and
Reform (FAIR) Act (P.L. 104-127), which prescribed farm commodity support policy through 2002
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