Reinhold A. Bertlmann, Katharina Durstberger, Yuji Hasegawa, Beatrix C. Hiesmayr

Phys.Rev.A69:032112,2004 Sep 2003

The influence of the geometric phase, in particular the Berry phase, on an
entangled spin-1/2 system is studied. We discuss in detail the case, where the
geometric phase is generated only by one part of the Hilbert space. We are able
to cancel the...

Yuji Hasegawa, Rudolf Loidl, Gerald Badurek, Matthias Baron, Helmut Rauch

Nov 2003

We report a single-neutron optical experiment to demonstrate the violation of
a Bell-like inequality. Entanglement is achieved not between particles, but
between the degrees of freedom, in this case, for a single-particle. The
spin-{\small 1/2} pr...

Stefan Filipp, Yuji Hasegawa, Rudolf Loidl, Helmut Rauch

Aug 2004

We present a split-beam neutron interferometric experiment to test the
non-cyclic geometric phase tied to the spatial evolution of the system: the
subjacent two-dimensional Hilbert space is spanned by the two possible paths in
the interferometer a...

Stefan Filipp, Yuji Hasegawa, Rudolf Loidl, Helmut Rauch

Phys. Rev. A 72, 021602(R) (2005) Dec 2004

We present a split-beam neutron interferometric experiment to test the
non-cyclic geometric phase tied to the spatial evolution of the system: the
subjacent two-dimensional Hilbert space is spanned by the two possible paths in
the interferometer a...

Reinhold A. Bertlmann, Katharina Durstberger, Yuji Hasegawa

Phys. Rev. A 73, 022111 (2006) Dec 2005

We study two different decoherence modes for entangled qubits by considering
a Liouville - von Neumann master equation. Mode A is determined by projection
operators onto the eigenstates of the Hamiltonian and mode B by projectors onto
rotated stat...

Adan Cabello, Stefan Filipp, Helmut Rauch, Yuji Hasegawa

Phys. Rev. Lett. 100 (2008) 130404 Apr 2008

We show that an experimental demonstration of quantum contextuality using 2
degrees of freedom of single neutrons based on a violation of an inequality
derived from the Peres-Mermin proof of the Kochen-Specker theorem would be more
conclusive than...

Yuji Hasegawa, Rudolf Loidl, Gerald Badurek, Stephan Sponar, Helmut Rauch

Aug 2009

We implemented a triply entangled Greenberger-Horne-Zeilinger(GHZ)-like state
and coherently manipulated the spin, path, and energy degrees of freedom in a
single neutron system. The GHZ-like state was analyzed with an inequality
derived by Mermin...

Yuji Hasegawa, Katharina Durstberger-Rennhofer, Stephan Sponar, Helmut Rauch

Apr 2010

The Kochen-Specker theorem theoretically shows evidence of the
incompatibility of noncontextual hidden variable theories with quantum
mechanics. Quantum contextuality is a more general concept than quantum
non-locality which is quite well tested i...

Entanglement between degrees of freedom, namely between the spin, path and
(total) energy degrees of freedom, for single neutrons is exploited. We
implemented a triply entangled Greenberger-Horne-Zeilinger(GHZ)-like state and
coherently manipulate...

Jacqueline Erhart, Stephan Sponar, Georg Sulyok, Gerald Badurek, Masanao Ozawa, Yuji Hasegawa

Jan 2012

The uncertainty principle generally prohibits determination of certain pairs
of quantum mechanical observables with arbitrary precision and forms the basis
of indeterminacy in quantum mechanics. It was Heisenberg who used the famous
gamma-ray micr...

Daniel Erdösi, Marcus Huber, Beatrix C. Hiesmayr, Yuji Hasegawa

New J. Phys. 15 (2013) 023033.
http://stacks.iop.org/1367-2630/15/023033 Dec 2012

We present experimental evidence of the generation of distinct types of
genuine multipartite entanglement between three degrees of freedom, two
internal and one external degree of freedom, within single-neutron quantum
systems. This is achieved vi...

Georg Sulyok, Stephan Sponar, Jacqueline Erhart, Gerald Badurek, Masanao Ozawa, Yuji Hasegawa

May 2013

In its original formulation, Heisenberg's uncertainty principle dealt with
the relationship between the error of a quantum measurement and the thereby
induced disturbance on the measured object. Meanwhile, Heisenberg's heuristic
arguments have tur...

Tobias Denkmayr, Hermann Geppert, Stephan Sponar, Hartmut Lemmel, Alexandre Matzkin, Jeff Tollaksen, Yuji Hasegawa

Nat. Commun. 5, 4492 (2014) Dec 2013

From its very beginning quantum theory has been revealing extraordinary and
counter-intuitive phenomena, such as wave-particle duality, Schrödinger cats
and quantum non-locality. In the study of quantum measurement, a process
involving pre- and ...

Hermann Geppert, Tobias Denkmayr, Stephan Sponar, Hartmut Lemmel, Yuji Hasegawa

Nuclear Inst. and Methods in Physics Research, A (2014), pp.
417-423 Apr 2014

For precise measurements with polarized neutrons high efficient
spin-manipulation is required. We developed several neutron optical elements
suitable for a new sophisticated setup, i.e., DC spin-turners and
Larmor-accelerators which diminish therm...

Stephan Sponar, Tobias Denkmayr, Hermann Geppert, Hartmut Lemmel, Alexandre Matzkin, Yuji Hasegawa

Phys. Rev. A 92, 062121 (2015) Apr 2014

Weak values of the spin operator Sz of massive particles, more precisely
neutrons, have been experimentally determined by applying a novel measurement
scheme. This is achieved by coupling the neutron's spin weakly to its spatial
degree of freedom ...

Georg Sulyok, Stephan Sponar, Buelent Demirel, Francesco Buscemi, Michael J. W. Hall, Masanao Ozawa, Yuji Hasegawa

Phys. Rev. Lett. 115, 030401 (2015) Apr 2015

Information-theoretic definitions for noise and disturbance in quantum
measurements were given in Phys. Rev. Lett. 112, 050401 (2014) and a
state-independent noise-disturbance uncertainty relation was obtained. Here, we
derive a tight noise-distur...

Bülent Demirel, Stephan Sponar, Georg Sulyok, Masanao Ozawa, Yuji Hasegawa

Phys. Rev. Lett. 117, 140402 (2016) Nov 2015

The indeterminacy inherent in quantum measurement is an outstanding character
of quantum theory, which manifests itself typically in Heisenberg's
error-disturbance uncertainty relation. In the last decade, Heisenberg's
relation has been generalize...

In quantum physics Wigner's rotation is commonly regarded as confirmed by the
Thomas precession in a hydrogen like atom. In this paper we show that a direct
experimental verification of Wigner's rotation is in principle accessible in
the regime of...

Tobias Denkmayr, Hermann Geppert, Hartmut Lemmel, Mordecai Waegell, Justin Dressel, Yuji Hasegawa, Stephan Sponar

Phys. Rev. Lett. 118, 010402 (2017) Apr 2016

A novel method was recently proposed and experimentally realized for
characterizing a quantum state by directly measuring its complex probability
amplitudes in a particular basis using so-called weak values. Recently Vallone
and Dequal showed theo...

Mordecai Waegell, Tobias Denkmayr, Hermann Geppert, David Ebner, Tobias Jenke, Yuji Hasegawa, Stephan Sponar, Justin Dressel, Jeff Tollaksen

Phys. Rev. A 96, 052131 (2017) Sep 2016

Previous experimental tests of quantum contextuality based on the
Bell-Kochen-Specker (BKS) theorem have demonstrated that not all observables
among a given set can be assigned noncontextual eigenvalue predictions, but
have never identified which ...

Bülent Demirel, Stephan Sponar, Alastair A. Abbott, Cyril Branciard, Yuji Hasegawa

Nov 2017

A tight information-theoretic measurement uncertainty relation is
experimentally tested with neutron spin-1/2 qubits. The noise associated to the
measurement of an observable is defined via conditional Shannon entropies and a
tradeoff relation bet...

Bülent Demirel, Stephan Sponar, Alastair A. Abbott, Cyril Branciard, Yuji Hasegawa

New J. Phys. 21, 013038 (2019) Nov 2017

A tight information-theoretic measurement uncertainty relation is
experimentally tested with neutron spin-1/2 qubits. The noise associated to the
measurement of an observable is defined via conditional Shannon entropies and a
tradeoff relation bet...

Armin Danner, Bülent Demirel, Wenzel Kersten, Richard Wagner, Hartmut Lemmel, Stephan Sponar, Yuji Hasegawa

Apr 2019

Einstein's theory of general relativity and quantum theory form the two major
pillars of modern physics. However, certain inertial properties of a particle's
intrinsic spin are inconspicuous while the inertial properties of mass are well
known. He...

Wenzel Kersten, Laurids Brandl, Richard Wagner, Christian Huber, Florian Bruckner, Yuji Hasegawa, Dieter Suess, Stephan Sponar

Phys. Rev. Applied 12, 014023 (2019) Oct 2018

In neutron interferometric experiments using polarized neutrons coherent
spin-rotation control is required. In this letter we present a new method for
Larmor spin-rotation around an axis parallel to the outer guide field using
topology optimized 3...