What is the Science behind offering the sacred thread (janave) to deities?

Offering the sacred thread to deities means binding the expanse of the brilliance of deities in the rounds of the sacred thread and evoking It to function in duality. As the janave is made of thread and is enriched with mantra-energy, the frequencies of sound emitted by it activate the attribute less principle of God from the universe. This then functions for the embodied soul (worshipper) as per its spiritual emotion towards God through the medium of the ‘with attributes’ frequencies. The sacred thread represents the silvery link between God, that is, non duality and the embodied soul, that is, duality. Offering the sacred thread in ritualistic worship is an important process of interaction of duality-non duality. Wearing this sacred thread after the ritualistic worship endows the wearer with the sattva predominant divine consciousness of the deity.’ – Pujya (Mrs.) Anjali Gadgil

Reference:

'What is the importance of the substances used in ritualistic worship?', published by Sanatan Sanstha.