Efficient quantum-state tomography for quantum-information processing using a two-dimensional Fourier-transform technique

Das, Ranabir; Mahesh, T. S.; Kumar, Anil

doi:10.1103/physreva.67.062304

Cited by 36 publications

(33 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The intensities of the peaks in the spectra provide a measure of the diagonal elements of the density matrix. The complete tomographed [40,41] density matrices in each case is given in figures 6(d), (f), (h) and (j).…”

Section: Deutsch-jozsa Algorithmmentioning

confidence: 99%

Use of non-adiabatic geometric phase for quantum computing by NMR

Das

Kumar

2005

Journal of Magnetic Resonance

Self Cite

View full text Add to dashboard Cite

Geometric phases have stimulated researchers for its potential applications in many areas of science. One of them is fault-tolerant quantum computation. A preliminary requisite of quantum computation is the implementation of controlled logic gates by controlled dynamics of qubits. In controlled dynamics, one qubit undergoes coherent evolution and acquires appropriate phase, depending on the state of other qubits. If the evolution is geometric, then the phase acquired depend only on the geometry of the path executed, and is robust against certain types of errors. This phenomenon leads to an inherently fault-tolerant quantum computation. Here we suggest a technique of using non-adiabatic geometric phase for quantum computation, using selective excitation. In a two-qubit system, we selectively evolve a suitable subsystem where the control qubit is in state |1 , through a closed circuit. By this evolution, the target qubit gains a phase controlled by the state of the control qubit. Using these geometric phase gates we demonstrate implementation of Deutsch-Jozsa algorithm and Grover's search algorithm in a two-qubit system.

show abstract

Section: Deutsch-jozsa Algorithmmentioning

confidence: 99%

Use of non-adiabatic geometric phase for quantum computing by NMR

Das

Kumar

2005

Journal of Magnetic Resonance

Self Cite

View full text Add to dashboard Cite

show abstract

“…The coherences will be converted into multiple quantum coherences which are not detected directly in NMR. Hence, the "spectral implementation" gives a measure of the deviation populations or probabilities of each state but does not measure the coherences, which if required can be measured by state tomography [30][31][32].…”

Section: Theorymentioning

confidence: 99%

“…The last step in any quantum information processing task is the "readout" of the output. Typically in NMR, the readout is obtained by selectively detecting spins [29], or by mapping out the full density matrix [30][31][32]. It was first pointed out by Ernst et.al.…”

Section: Introductionmentioning

confidence: 99%

Spectral implementation of some quantum algorithms by one- and two-dimensional nuclear magnetic resonance

Das

Kumar

2004

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Quantum information processing has been effectively demonstrated on a small number of qubits by nuclear magnetic resonance. An important subroutine in any computing is the readout of the output. "Spectral implementation" originally suggested by Z.L. Madi, R. Bruschweiler and R.R. Ernst, [J. Chem. Phys. 109, 10603 (1999)], provides an elegant method of readout with the use of an extra 'observer' qubit. At the end of computation, detection of the observer qubit provides the output via the multiplet structure of its spectrum. In "spectral implementation" by two-dimensional experiment the observer qubit retains the memory of input state during computation, thereby providing correlated information on input and output, in the same spectrum. "Spectral implementation" of Grover's search algorithm, approximate quantum counting, a modified version of Berstein-Vazirani problem, and Hogg's algorithm is demonstrated here in three and four-qubit systems.

show abstract

“…In the standard method, the required number of independent experiments grows exponentially with the number of input qubits [26,27]. Anil Kumar and co-workers have illustrated QST using a single twodimensional NMR spectrum [28]. Later Nieuwenhuizen and co-workers showed how to reduce the number of independent experiments in the presence of an ancilla register [29].…”

Section: Ancilla Assisted Quantum State Tomographymentioning

confidence: 99%

Ancilla-Assisted Measurements on Quantum Ensembles: General Protocols and Applications in NMR Quantum Information Processing

Mahesh¹,

Shukla²,

Hegde³

et al. 2015

Current Science

Self Cite

View full text Add to dashboard Cite

Quantum ensembles form easily accessible architectures for studying various phenomena in quantum physics, quantum information science, and spectroscopy. Here we review some recent protocols for measurements in quantum ensembles by utilizing ancillary systems. We also illustrate these protocols experimentally via nuclear magnetic resonance techniques. In particular, we shall review noninvasive measurements, extracting expectation values of various operators, characterizations of quantum states, and quantum processes, and finally quantum noise engineering.

show abstract

Efficient quantum-state tomography for quantum-information processing using a two-dimensional Fourier-transform technique

Cited by 36 publications

References 26 publications

Use of non-adiabatic geometric phase for quantum computing by NMR

Use of non-adiabatic geometric phase for quantum computing by NMR

Spectral implementation of some quantum algorithms by one- and two-dimensional nuclear magnetic resonance

Ancilla-Assisted Measurements on Quantum Ensembles: General Protocols and Applications in NMR Quantum Information Processing

Contact Info

Product

Resources

About