Table 2 Possible values of M and relative states. We consider ε2 < 0

From: Spectral properties of two superconducting artificial atoms coupled to a resonator in the ultrastrong coupling regime

m1

−1

+1

−1

+1

m2

−1

−1

+1

+1

M

0

+2

−2

0

States if ε1 < 0

\(\left\vert gg\right\rangle \left\vert 0\right\rangle\)

\(\left\vert eg\right\rangle \left\vert -\alpha \right\rangle\)

\(\left\vert ge\right\rangle \left\vert+\alpha \right\rangle\)

\(\left\vert ee\right\rangle \left\vert 0\right\rangle\)

M+

+2

0

0

−2

States if ε1 > 0

\(\left\vert gg\right\rangle \left\vert+\alpha \right\rangle\)

\(\left\vert eg\right\rangle \left\vert 0\right\rangle\)

\(\left\vert ge\right\rangle \left\vert 0\right\rangle\)

\(\left\vert ee\right\rangle \left\vert -\alpha \right\rangle\)