Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improving resilience of the Quantum Gravity Induced Entanglement of
  Masses (QGEM) to decoherence using 3 superpositions   Recently a protocol called quantum gravity induced entanglement of masses
(QGEM) that aims to test the quantum nature of gravity using the entanglement
of 2 qubits was proposed. The entanglement can arise only if the force between
the two spatially superposed masses is occurring via the exchange of a
mediating virtual graviton. In this paper, we examine a possible improvement of
the QGEM setup by introducing a third mass with an embedded qubit, so that
there are now 3 qubits to witness the gravitationally generated entanglement.
We compare the entanglement generation for different experimental setups with 2
and 3 qubits and find that a 3-qubit setup where the superpositions are
parallel to each other leads to the highest rate of entanglement generation
within $\tau = 5 $ s. We will show that the 3-qubit setup is more resilient to
the higher rate of decoherence. The entanglement can be detected experimentally
for the 2-qubit setup if the decoherence rate $\gamma$ is $\gamma < 0.11 $ Hz
compared to $\gamma < 0.16 $ Hz for the 3-qubit setup. However, the
introduction of an extra qubit means that more measurements are required to
characterize entanglement in an experiment. We conduct experimental simulations
and estimate that the 3-qubit setup would allow detecting the entanglement in
the QGEM protocol at a $99.9\%$ certainty with $O(10^4)-O(10^5)$ measurements
when $\gamma \in [0.1,0.15] $ Hz. Furthermore, we find that the number of
needed measurements can be reduced to $O(10^3)-O(10^5)$ if the measurement
schedule is optimised using joint Pauli basis measurements. For $\gamma > 0.06
$ Hz the 3-qubit setup is favourable compared to the 2-qubit setup in terms of
the minimum number of measurements needed to characterize the entanglement.
Thus, the proposed setup here provides a promising new avenue for implementing
the QGEM experiment.

35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an