Victor V. Flambaum

The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9 (2009)

Henkel, Christian, Menten, K. M., Murphy, M. T., Jethava, N., Flambaum, Victor V., Braatz, James A., ...

Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS 1830–211, which is by far the best known...

The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9 (2009)

Henkel, Christian, Menten, K. M., Murphy, M. T., Jethava, N., Flambaum, Victor V., Braatz, James A., ...

Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS 1830–211, which is by far the best known...

Strong Limit on a Variable Proton-to-Electron Mass Ratio from Molecules in the Distant Universe (2008)

Murphy, Michael T., Flambaum, Victor V., Muller, Sebastien, Henkel, Christian

The Standard Model of particle physics assumes that the so-called fundamental constants are universal and unchanging. Absorption lines arising in molecular clouds along quasar sightlines offer a...

Strong limit on a variable proton-to-electron mass ratio from molecules in the distant universe (2008)

Murphy, Michael T., Flambaum, Victor V., Muller, Sébastien, Henkel, Christian

The Standard Model of particle physics assumes that the so-called fundamental constants are universal and unchanging. Absorption lines arising in molecular clouds along quasar sightlines offer a...

Strong limit on a variable proton-to-electron mass ratio from molecules in the distant universe (2008)

Murphy, Michael T., Flambaum, Victor V., Muller, Sébastien, Henkel, Christian

The Standard Model of particle physics assumes that the so-called fundamental constants are universal and unchanging. Absorption lines arising in molecular clouds along quasar sightlines offer a...

Revision of VLT/UVES constraints on a varying fine-structure constant (2008)

Murphy, M. T., Webb, J. K., Flambaum, Victor V.

We critically review the current null results on a varying fine-structure constant, α, derived from Very Large Telescope (VLT)/Ultraviolet and Visual Echelle Spectrograph (UVES) quasar...

Strong limit on a variable proton-to-electron mass ratio from molecules in the distant universe (2008)

Murphy, Michael T., Flambaum, Victor V., Muller, Sebastien, Henkel, Christian

The Standard Model of particle physics assumes that the so-called fundamental constants are universal and unchanging. Absorption lines arising in molecular clouds along quasar sightlines offer a...

Strong limit on a variable proton-to-electron mass ratio from molecules in the distant universe (2008)

Murphy, Michael T., Flambaum, Victor V., Muller, Sebastien, Henkel, Christian

The Standard Model of particle physics assumes that the so-called fundamental constants are universal and unchanging. Absorption lines arising in molecular clouds along quasar sightlines offer a...

Revision of VLT/UVES constraints on a varying fine-structure constant (2008)

Murphy, M. T., Webb, J. K., Flambaum, Victor V.

We critically review the current null results on a varying fine-structure constant, α, derived from Very Large Telescope (VLT)/Ultraviolet and Visual Echelle Spectrograph (UVES) quasar absorption...

Comment on "Limits on the Time Variation of the Electromagnetic Fine-Structure Constant in the Low Energy Limit from Absorption Lines in the Spectra of Distant Quasars" (2007)

Murphy, Michael T., Webb, John K., Flambaum, Victor V.

In their Letter [Phys. Rev. Lett. 92, 121302 (2004)] (also [Astron. Astrophys. 417, 853 (2004)]), Srianand et al. analysed optical spectra of heavy-element species in 23 absorption systems along...

Probing variations in fundamental constants with radio and optical quasar absorption-line observations (2007)

Tzanavaris, Panayiotis, Murphy, Michael T., Webb, Jonathan K., Flambaum, Victor V., Curran, Stephen J.

Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x equivalent to alpha(2)g(p)mu, where alpha is the fine structure...

Probing variations in fundamental constants with radio and optical quasar absorption-line observations (2007)

Tzanavaris, Panayiotis, Murphy, Michael T., Webb, Jonathan K., Flambaum, Victor V., Curran, Stephen J.

Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x equivalent to alpha(2)g(p)mu, where alpha is the fine structure...

Probing variations in fundamental constants with radio and optical quasar absorption-line observations (2007)

Tzanavaris, Panayiotis, Murphy, Michael T., Webb, Jonathan K., Flambaum, Victor V., Curran, Stephen J.

Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x equivalent to alpha(2)g(p)mu, where alpha is the fine structure...

Probing variations in fundamental constants with radio and optical quasar absorption-line observations (2007)

Tzanavaris, Panayiotis, Murphy, Michael T., Webb, J. K., Flambaum, Victor V., Curran, Stephen J.

Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x equivalent to alpha(2)g(p)mu, where alpha is the fine structure...

Probing variations in fundamental constants with radio and optical quasar absorption-line observations (2007)

Tzanavaris, Panayiotis, Murphy, Michael T., Webb, J. K., Flambaum, Victor V., Curran, Stephen J.

Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x equivalent to alpha(2)g(p)mu, where alpha is the fine structure...

Revision of VLT/UVES constraints on a varying fine-structure constant (2006)

Murphy, Michael T., Webb, John K., Flambaum, Victor V.

We critically review the current null results on a varying fine-structure constant, alpha, derived from VLT/UVES quasar absorption spectra, focusing primarily on the many-multiplet analysis of 23...

Constraining variations in the fine-structure constant, quark masses and the strong interaction (2004)

Murphy, Michael T., Flambaum, Victor V., Webb, J. K., Dzuba, Vladimir V., Prochaska, Jason X., Wolfe, Arthur M.

We present evidence for variations in the fine-structure constant from Keck/HIRES spectra of 143 quasar absorption systems over the redshift range 0.2 < zabs < 4.2. This includes 15 new systems,...

Constraining variations in the fine-structure constant, quark masses and the strong interaction (2004)

Murphy, Michael T., Flambaum, Victor V., Webb, J. K., Dzuba, Vladimir V., Prochaska, Jason X., Wolfe, Arthur M.

We present evidence for variations in the fine-structure constant from Keck/HIRES spectra of 143 quasar absorption systems over the redshift range 0.2 < zabs < 4.2. This includes 15 new systems,...

Does the fine structure constant vary?: a third quasar absorption sample consistent with varying alpha (2003)

Webb, J. K., Murphy, Michael T., Flambaum, Victor V., Curran, Stephen J.

We report results from a third sample of quasar absorption line spectra from the Keck telescope which has been studied to search for any possible variation of the fine structure constant, α. This...

Further evidence for a variable fine-structure constant from Keck/HIRES QSO absorption spectra (2003)

Murphy, M. T., Webb, J. K., Flambaum, Victor V.

We have previously presented evidence for a varying fine-structure constant, α, in two independent samples of Keck/HIRES quasi-stellar object (QSO) absorption spectra. Here we present a detailed...

Does the fine structure constant vary?: a detailed investigation into systematic effects (2003)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Curran, Stephen J.

We have previously presented 5.7 σ evidence for a smaller αat redshifts 0.2 < zabs < 3.7 from a sample of 128 Keck/HIRES quasar absorption systems: Δα/α = (-0.57 ± 0.10) x10-5. A non-zero

Does the fine structure constant vary?: a third quasar absorption sample consistent with varying alpha (2003)

Webb, J. K., Murphy, Michael T., Flambaum, Victor V., Curran, Stephen J.

We report results from a third sample of quasar absorption line spectra from the Keck telescope which has been studied to search for any possible variation of the fine structure constant, α. This...

Further evidence for a variable fine-structure constant from Keck/HIRES QSO absorption spectra (2003)

Murphy, M. T., Webb, J. K., Flambaum, Victor V.

We have previously presented evidence for a varying fine-structure constant, α, in two independent samples of Keck/HIRES quasi-stellar object (QSO) absorption spectra. Here we present a detailed...

Does the fine structure constant vary?: a detailed investigation into systematic effects (2003)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Curran, Stephen J.

We have previously presented 5.7 σ evidence for a smaller αat redshifts 0.2 < zabs < 3.7 from a sample of 128 Keck/HIRES quasar absorption systems: Δα/α = (-0.57 ± 0.10) x10-5. A non-zero

Time evolution of the fine structure constant (2002)

Murphy, Michael T., Webb, J. K., Flambaum, Victor V., Curran, Stephen J.

We present a short review of the current quasar (QSO) absorption line constraints on possible variation of the fine structure constant, α ≡ e2/¯hc. Particular attention is paid to...

A catalogue of damped Lyman alpha absorption systems and radio flux densities of the background quasars (2002)

Curran, Stephen J., Webb, J. K., Murphy, M. T., Bandiera, Rino, Corbelli, Edvige, Flambaum, Victor V.

We present a catalogue of the 322 damped Lyman alpha absorbers taken from the literature. All damped Lyman alpha absorbers are included, with no selection on redshift or quasar magnitude. Of these,...

Time evolution of the fine structure constant (2002)

Murphy, Michael T., Webb, J. K., Flambaum, Victor V., Curran, Stephen J.

We present a short review of the current quasar (QSO) absorption line constraints on possible variation of the fine structure constant, α ≡ e2/¯hc. Particular attention is paid to...

A catalogue of damped Lyman alpha absorption systems and radio flux densities of the background quasars (2002)

Curran, Stephen J., Webb, J. K., Murphy, M. T., Bandiera, Rino, Corbelli, Edvige, Flambaum, Victor V.

We present a catalogue of the 322 damped Lyman alpha absorbers taken from the literature. All damped Lyman alpha absorbers are included, with no selection on redshift or quasar magnitude. Of these,...

Possible evidence for a variable fine-structure constant from QSO absorption lines: motivations, analysis and results (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Dzuba, V. A., Churchill, Christopher W., Prochaska, Jason X., ...

An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar (QSO) absorption-line spectra with...

Possible evidence for a variable fine-structure constant from QSO absorption lines: systematic errors (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Churchill, Christopher W., Prochaska, Jason X.

Comparison of quasar (QSO) absorption spectra with laboratory spectra allows us to probe possible variations in the fundamental constants over cosmological time-scales. In a companion paper we...

Relativistic effects in NiII and the search for variation of the fine-structure constant (2001)

Dzuba, V. A., Flambaum, Victor V., Murphy, M. T., Webb, J. K.

Theories unifying gravity and other interactions suggest the possibility of spatial and temporal variation of physical “constants” in the Universe. Detection of high redshift absorption...

Further evidence for cosmological evolution of the fine structure constant (2001)

Webb, J. K., Murphy, M. T., Flambaum, Victor V., Dzuba, V. A., Barrow, John D., Churchill, Christopher W., ...

We describe the results of a search for time variability of the fine structure constant α using absorption systems in the spectra of distant quasars. Three large optical data sets and two 21 cm...

Improved constraints on possible variation of physical constants from HI 21-cm and molecular QSO absorption lines (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Drinkwater, Michael J., Combes, Francoise, Wiklind, Tommy

Quasar (QSO) absorption spectra provide an extremely useful probe of possible cosmological variation in various physical constants. Comparison of HI 21-cm absorption with corresponding molecular...

Relativistic corrections in atoms and space-time variation of the fine structure constant (2001)

Dzuba, V. A., Flambaum, Victor V., Murphy, Michael T., Webb, J. K.

Comparison of quasar absorption line spectra with laboratory spectra provides the best probe for variability of the fine structure constant, α = e 2/ħc, over cosmological time-scales. We...

Further constraints on variation of the fine-structure constant from alkali-doublet QSO absorption lines (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Prochaska, Jason X., Wolfe, Arthur M.

Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a precise probe for variability of the fine-structure constant, α, over cosmological time-scales. We...

Possible evidence for a variable fine-structure constant from QSO absorption lines: motivations, analysis and results (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Dzuba, V. A., Churchill, Christopher W., Prochaska, Jason X., ...

An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar (QSO) absorption-line spectra with...

Possible evidence for a variable fine-structure constant from QSO absorption lines: systematic errors (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Churchill, Christopher W., Prochaska, Jason X.

Comparison of quasar (QSO) absorption spectra with laboratory spectra allows us to probe possible variations in the fundamental constants over cosmological time-scales. In a companion paper we...

Relativistic effects in NiII and the search for variation of the fine-structure constant (2001)

Dzuba, V. A., Flambaum, Victor V., Murphy, M. T., Webb, J. K.

Theories unifying gravity and other interactions suggest the possibility of spatial and temporal variation of physical “constants” in the Universe. Detection of high redshift absorption...

Further evidence for cosmological evolution of the fine structure constant (2001)

Webb, J. K., Murphy, M. T., Flambaum, Victor V., Dzuba, V. A., Barrow, John D., Churchill, Christopher W., ...

We describe the results of a search for time variability of the fine structure constant α using absorption systems in the spectra of distant quasars. Three large optical data sets and two 21 cm...

Improved constraints on possible variation of physical constants from HI 21-cm and molecular QSO absorption lines (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Drinkwater, Michael J., Combes, Francoise, Wiklind, Tommy

Quasar (QSO) absorption spectra provide an extremely useful probe of possible cosmological variation in various physical constants. Comparison of HI 21-cm absorption with corresponding molecular...

Relativistic corrections in atoms and space-time variation of the fine structure constant (2001)

Dzuba, V. A., Flambaum, Victor V., Murphy, Michael T., Webb, J. K.

Comparison of quasar absorption line spectra with laboratory spectra provides the best probe for variability of the fine structure constant, α = e 2/ħc, over cosmological time-scales. We...

Further constraints on variation of the fine-structure constant from alkali-doublet QSO absorption lines (2001)

Murphy, M. T., Webb, J. K., Flambaum, Victor V., Prochaska, Jason X., Wolfe, Arthur M.

Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a precise probe for variability of the fine-structure constant, α, over cosmological time-scales. We...

A Search for Time Variation of the Fine Structure Constant (1998)

Webb, John K., Flambaum, Victor V., Churchill, Christopher W., Drinkwater, Michael J., Barrow, John D.

A method offering an order of magnitude sensitivity gain is described for using quasar spectra to investigate possible time or space variation in the fine structure constant, alpha. Applying the...