Hart sent threatening e-mails to the 24-year-old woman, with such warnings as "You called the cops but they can't do anything" and "How would you like it if your sister went missing?"
Those e-mails were automatically deleted from her computer inbox 20 minutes after she opened them and before she could show them to police. A police officer later sat at the woman's computer to view the next incoming message.
Hart also used "SpoofCard.com" - one of the online services that allow callers to hide their phone numbers and even change the sound of their voices - to make threatening calls.
In one e-mail threat, he said, "You're going to [obscenity] die." In another, Hart said the woman had 10 days to leave California "or else."
Hart was convicted on charges of stalking and invasion of privacy.
Prosecutors believe that on one night, Hart sent a sewer repairman, a pizza deliveryman, and an electrician to her father's house.
After a short relationship - started on an online dating site - Hart was angered when the woman announced that she was moving to California to take an internship at Lawrence Livermore National Laboratories.
The woman said she had lived with Hart briefly before she moved to California. She was later mysteriously withdrawn from the University of Medicine and Dentistry of New Jersey - where she had been studying for a graduate degree in biomedical science - without her knowledge.
Her registration to take the Medical College Aptitude Test was also canceled without her knowledge.
The woman said her sister and other relatives also received threatening calls from Hart.
After the sentencing, the woman said she was relieved that Hart was going to prison, although she wanted a stiffer punishment.
"I wish he would have gotten more time," the woman said. "My credit score took a hit. I've managed to get back on my feet a little, but during the damage, I lost a lot of money."
The woman said that she had resumed her college studies and planned to attend medical school.
Assistant U.S. Attorney Michael Levy, who prosecuted the case, said Hart had a conviction in New Jersey in 2003 for stalking a woman. In 2005, he was convicted of invasion of privacy for hiding in a women's bathroom at Immaculata University in Chester County and videotaping students as they used the toilet.
Padova called Hart's criminal record "ominous and serious," adding that he had "a history of harassing and invading the privacy of women."
The judge said: "Even after the arrest . . . this defendant's egregious conduct did not end."
Addressing the court before sentencing, Hart said: "First, I want to [say] how sorry I am."
He added: "Part of it was depression, and part of it was anger.
"I was upset that she wasn't speaking to me, and I didn't want her to go. I was being selfish."
Contact staff writer Vernon Clark at 215-854-5717 or firstname.lastname@example.org.