Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fast partial decoherence of a superconducting flux qubit in a spin bath   The superconducting flux qubit has two quantum states with opposite magnetic
flux. Environment of nuclear spins can find out the direction of the magnetic
flux after a decoherence time $\tau_0$ inversely proportional to the magnitude
of the flux and the square root of the number of spins. When the Hamiltonian of
the qubit drives fast coherent Rabi oscillations between the states with
opposite flux, then flux direction is flipped at a constant rate $\omega$ and
the decoherence time $\tau=\omega\tau_0^2$ is much longer than $\tau_0$.
However, on closer inspection decoherence actually takes place on two
timescales. The long time $\tau$ is a time of full decoherence but a part of
quantum coherence is lost already after the short time $\tau_0$. This fast
partial decoherence biases coherent flux oscillations towards the initial flux
direction and it can affect performance of the superconducting devices as
qubits.

13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
2
The categories of this paper are: math
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con