Is it allowed to recite or Listen Quran in the digital(On leptop or mobile pdf's or mp3's) form without Wudu?
Narrated 'Aisha: "The Prophet used to recite the Quran with his head in my lap while I used to be in my periods (having menses). (Translation of Sahih Bukhari, ONENESS, UNIQUENESS OF ALLAH (TAWHEED), Volume 9, Book 93, Number 639)
So, I guess the above hadith clearly answers your question. And in fact it answers in general to this...
Can we listen to Qur'an without wudu?
As, in the hadith, Ayesha(RA) was listening to Qur'an in a state far worse from not being in a state of wudu while the Prophet(pbuh) is witnessing.
May the creator guide us all.