This is Tzu-Chieh Wei’s homepage located at Perimeter Institute. I am currently a postdoctoral fellow associated with Dr. Michele Mosca and Dr. Ashwin Nayak. I'm based in IQC and my affiliation with PI is through Dr. Mosca and Dr. Nayak.

I received my PhD in physics in Oct. 2004 from the University of Illinois at Urbana-Champaign, working on entanglement theory with Prof. Paul Goldbart and on entangled photons and their applications in quantum information processing with Prof. Paul Kwiat. After obtaining my degree there, I stayed and focused my research on condensed matter, mainly on superconductivity, BEC, and optical lattices. During my career in UIUC, I have cultivated my interests in both condensed matter physics and quantum information science, and have collaborated closely with experimental groups such as Kwiat's Quantum Information Group and Bezryadin's Low Temperature Physics Lab. In addition, I have collaborated with Prof. Brian DeMarco and Prof. Smitha Vishveshwara.

I moved from Urbana-Champaign to Waterloo in Sep. 2007.


My papers on arXiv


Here is my brief CV:




PhD   Physics, University of Illinois at Urbana-Champaign (UIUC),  October 2004

Dissertation title: “Quantum entanglement: geometric quantification and applications to multi-partite states and quantum phase transitions”

Under supervision of Prof. Paul M. Goldbart

M. S.  Physics, National Taiwan University (NTU), June 1996

      Thesis title: “Glueball mass calculation”

      Under supervision of Prof. Ting Wai Chiu

B. A.  Physics, National Taiwan University, June 1994


Positions and Related Experience


Postdoctoral Research Fellow, IQC Sep 2007 -- present

Postdoctoral Research Associate, UIUC Sep 2004 – Aug 2007 

Graduate Research Assistant, UIUC 2001 -- 2004 

Graduate Research Assistant, NTU 1994 – 1996


Honors and Awards


1. John Bardeen Award, 2004

2. Harry G. Drickamer Graduate Fellowship, 2003

3. Mavis Memorial Fund Scholarship Award, 2002

4. Member of the Honor Society of Phi Kappa Phi

5. The Ministry of Education Graduate Fellowship, Taiwan, 1994 – 1996

6. Scholarship for Gifted Senior High School Students Studying Mathematics and
    Natural Sciences (Ministry of Education, Taiwan), 1990 – 1994



last updated: May, 2009


Peer-Reviewed Papers


1. "Maximal entanglement versus entropy for mixed quantum states,"

T.-C. Wei, K. Nemoto, P.M. Goldbart, P.G. Kwiat, W.J. Munro, and F. Verstraete,

Phys. Rev A 67, 022110 (2003)


2. "Ancilla-assisted quantum process tomography," J.B. Altepeter, D. Branning,

E. Jeffrey, T.-C. Wei, P.G. Kwiat, R.T. Thew, J.L. O'Brien, M.A. Nielsen, and

A.G. White, Phys. Rev. Lett. 90, 193601 (2003)


3. "Geometric measure of entanglement for bipartite and multipartite quantum states,"

T.-C. Wei and P.M. Goldbart, Phys. Rev. A 68, 042307 (2003)                   


4. "Maximally entangled mixed states: creation and concentration,"

N.A. Peters, J.B. Altepeter, D.A. Branning, E.R. Jeffrey, T.-C. Wei, and P.G. Kwiat,

Phys. Rev.  Lett. 92, 133601 (2004).

Erratum: “Maximally Entangled Mixed States: Creation and Concentration” [Phys. Rev. Lett. 92, 133601 (2004)]
Nicholas A. Peters et al.
Phys. Rev. Lett. 96, 159901 (E) (2006)


5. "Measures of entanglement in bound entangled states"

T.-C. Wei, J.B. Altepeter, P.M. Goldbart, and W.J. Munro, Phys. Rev. A 70, 022322 (2004);

eprint quant-ph/0308031.


6.  "Synthesizing arbitrary two-photon polarization mixed states,"

Tzu-Chieh Wei, Joseph B. Altepeter, David Branning, Paul M. Goldbart,

D. F. V. James, Evan Jeffrey, Paul G. Kwiat, Swagatam Mukhopadhyay,

and Nicholas A. Peters, Phys. Rev. A 71, 032329 (2005); quant-ph/0501122


7. "Connections between relative entropy of entanglement and geometric measure of entanglement," Tzu-Chieh Wei, Marie Ericsson, Paul M. Goldbart, and

William J. Munro, Quantum Info. Comput. v4, p.252-272 (2004);

eprint quant-ph/0405002.


8. "h/e magnetic flux modulation of the energy gap in nanotube quantum dots,"

Ulas C. Coskun, Tzu-Chieh Wei, Smitha Vishveshwara, Paul M. Goldbart, and

Alexey Bezryadin, Science v.304, p.1132-1134 (2004)


9. "Global entanglement and quantum criticality in spin chains," Tzu-Chieh Wei, Dyutiman Das, Swagatam Mukhopadyay, Smitha Vishveshwara, and Paul M. Goldbart,

Phys. Rev. A 71, 060305(R) (2005).


10. "Mixed state sensitivity of several quantum information benchmarks",

Nicholas A. Peters, Tzu-Chieh Wei, and Paul G. Kwiat, 

Phys. Rev. A 70, 052309 (2004) ; quant-ph/0407172


11. "Remote state preparation: arbitrary remote control of photon polarization",

Nicholas A. Peters, Julio Barreiro, Michael E. Goggin, Tzu-Chieh Wei, and Paul G. Kwiat, Phys. Rev. Lett. 94, 150502 (2005)


12. "Structure and stability of Mott-insulator shells of bosons trapped in an optical lattice", B. DeMarco, C. Lannert, S. Vishveshwara, and T.-C. Wei, Phys. Rev. A 71, 063601 (2005)

Erratum: “Structure and stability of Mott-insulator shells of bosons trapped in an optical lattice” [Phys. Rev. A 71, 063601 (2005)]
B. DeMarco et al. Phys. Rev. A 73, 049903 (E) (2006)


13. "Enhancing superconductivity: Magnetic impurities and their quenching by magnetic fields", T.-C. Wei, D. Pekker, A. Rogachev, A. Bezryadin, and P. M. Goldbart, cond-mat/0510476, Europhys Lett. 75, 943 (2006)


14. "Magnetic field enhancement of superconductivity in ultra-narrow wires", A. Rogachev, T.-C. Wei, D. Pekker, A.T. Bollinger, P. M. Goldbart, A. Bezryadin, cond-mat/0604351,  Phys. Rev. Lett. 97, 137001 (2006).


15. "The dynamics of condensate shells: collective modes and expansion", C. Lannert, T.-C. Wei, S. Vishveshwara, Phys. Rev. A 75, 013611 (2007),  cond-mat/0604455


16. “Hyperentangled Bell-state analysis”, Tzu-Chieh Wei, Julio T. Barreiro, and Paul G. Kwiat, Phys. Rev. A 75, 060305(R) (2007)


17. “Local superfluid densities probed via current-induced superconducting phase gradients”, David S. Hopkins, David Pekker, Tzu-Chieh Wei, Paul M. Goldbart, and Alexey Bezryadin, Phys. Rev. B 76, 220506 (R) (2007)


18. “Beating the channel capacity limit for linear photonic superdense coding”, Julio T. Barreiro, Tzu-Chieh Wei, and Paul G. Kwiat, Nature Phys. 4, 282-286 (2008)


See view and news by S.P. Walborn, Nature Phys. 4, 268 (2008)


19. “Emergence of $h/e$-period oscillations in the critical temperature of small superconducting rings threaded by magnetic flux”, Tzu-Chieh Wei and Paul M. Goldbart, Phys. Rev. B 77, 224512 (2008); arXiv:0712.2596


20. “Evidence for Quantum Phase Slip Events in Superconducting Nanowires at High Bias Current”, Mitrabhanu Sahu, Myung-Ho Bae, Andrey Rogachev, David Pekker, Tzu-Chieh Wei, Nayana Shah, Paul M. Goldbart and Alexey Bezryadin, arXiv:0804.2251, Nature Phys. doi:10.1038/NPHYS1276


21. “Relative entropy of entanglement for multipartite mixed states: Permutation-invariant states and Dur states”, Tzu-Chieh Wei, Phys. Rev. A 78, 012327 (2008); arXiv:0805.1090


22. “Transverse field-induced effects in carbon nanotubes”, Wade DeGottardi, Tzu-Chieh Wei, and Smitha Vishveshwara, Phys. Rev. B, 79, 205421 (2009); arXiv:0812.1851


Manuscripts in Preparation


1. “Entanglement under the renormalization-group transformations on quantum states and quantum phase transitions using matrix product states”, Tzu-Chieh Wei, e-print arXiv:0810.2564 (2008)


2. “Revisiting the critical velocity of a clean one-dimensional superconductor ”, Tzu-Chieh Wei and Paul M. Goldbart, e-print arXiv:0904.2409 (2009)


3. “Matrix permanent and quantum entanglement of permutation invariant states ”, Tzu-Chieh Wei and Simone Severini, e-print arXiv:0905.0012 (2009)


4. “Interacting boson problems are QMA-hard ”, Tzu-Chieh Wei, Michele Mosca, and Ashwin Nayak, e-print arXiv:0905.3413 (2009)


5. “Maximally entangled three-qubit states via geometric measure of entanglement ”, Sayatnova Tamaryan, Tzu-Chieh Wei and DaeKil Park, e-print arXiv:0905.3791 (2009)


6. “The geometric measure of entanglement for symmetric states ”, R. Huebener, M. Kleinmann, T.-C. Wei, and O. Guehne, arXiv:0905.4822 (2009)



My research interests


(1) Quantum Information Science

(2)  Condensed Matter Physics: superconductivity, superfluidity, and carbon nanotubes

(3)  Cold atoms and optical lattices

(4)  Complexity theory and approximation algorithms