Lithium abundances are presented for 91 dwarf and subgiant stars in the Galactic bulge .
The analysis is based on line synthesis of the ^ { 7 } Li line at 6707 Å in high-resolution spectra obtained during gravitational microlensing events , when the brightnesses of the targets were highly magnified .
Our main finding is that the bulge stars at sub-solar metallicities , and that are older than about eight billion years , does not show any sign of Li production , that is , the Li trend with metallicity is flat ( or even slightly declining ) .
This indicates that no lithium was produced during the first few billion years in the history of the bulge .
This finding is essentially identical to what is seen for the ( old ) thick disk stars in the Solar neighbourhood , and adds another piece of evidence for a tight connection between the metal-poor bulge and the Galactic thick disk .
For the bulge stars younger than about eight billion years , the sample contains a group of stars at very high metallicities at [ Fe / H ] \approx + 0.4 that have lithium abundances in the range A ( Li ) = 2.6 - 2.8 .
In the Solar neighbourhood the lithium abundances have been found to peak at a A ( Li ) \approx 3.3 at [ Fe / H ] \approx + 0.1 and then decrease by 0.4 - 0.5 dex when reaching [ Fe / H ] \approx + 0.4 .
The few bulge stars that we have at these metallicities , seem to support this declining A ( Li ) trend .
This could indeed support the recent claim that the low A ( Li ) abundances at the highest metallicities seen in the Solar neighbourhood could be due to stars from the inner disk , or the bulge region , that have migrated to the Solar neighbourhood .