What does beloved represent and could the idea of a ghost mean more than we thought?

In the story Beloved by Toni Morrison, it is questioned whether or not the child named Beloved turned into a ghost. After she died, a woman came to the family who manifested her character. The mother Sethe seems to believe her child came back to haunt her. There are a few different signs that could prove it and there is also the impact the woman has on Sethe. In the story beloved, what makes a ghost a ghost? Could it be psychological damage from Sethe having been a slave, raped, beaten, and living with the fact that she killed her daughter to save her from the same fate? What does beloved represent and could the idea of a ghost mean more than we thought?