A Gurbani field similar to Essence of mantras or the singularity that gives the benefits of repeated reciting of various Sikh compositions from Gurus and of the original text. Or a zenith field of mantras 
The below passages will give you an idea of the power of Gurbani Mantars.
Quote
Chronic diseases can be cured by Mantras. Chanting of Mantras generates potent spiritual waves or divine vibrations. They penetrate the physical and astral bodies of the patients and remove the root-causes of the sufferings. They fill the cells with pure Sattva or divine energy. They destroy the microbes and vivify the cells and tissues. They are the best and most potent antiseptics and germicides. They are more potent than ultra-violet rays or Roentgen rays.
He who has attained Mantra Siddhi, can cure cobra-bite or scorpion-bite or any chronic disease by mere touch on the affected part. When a man is bitten by a cobra a telegram is sent to the Mantra Siddha. The Mantra Siddha recites the Mantra and the man who is bitten by a cobra is cured. Does this not prove the tremendous power of Mantra?