 |
|
Subscribers:
to view the full text of a paper, click on the title of the paper. If you
have any problem to access the full text, please check with your librarian
or contact
qic@rintonpress.com
To subscribe to QIC, please click
Here.
|
Quantum
Information and Computation
ISSN: 1533-7146
published since 2001
|
|
Vol.2 No.3, April 2002 |
|
Quantum algorithm for measuring the
eigenvalues of UÄU-1
for a black-box unitary
transformation U
(pp192-197)
Dominik
Janzing and
Thomas Beth
doi:
https://doi.org/10.26421/QIC2.3-2
Abstracts:
Estimating the eigenvalues of a unitary transformation U by
standard phase estimation requires the implementation of controlled-U-gates
which are not available if U is only given as a black box. We show that
a simple trick allows to measure eigenvalues of U\otimesU^\deggar even
in this case. Running the algorithm several times allows therefore to
estimate the autocorrelation function of the density of eigenstates of U.
This can be applied to find periodicities in the energy spectrum of a
quantum system with unknown Hamiltonian if it can be coupled to a
quantum computer.
Key words:
measurements, energy gaps, quantum phase estimation, spectral gaps,
auto-correlation |
¡¡ |
