Detection of a Disorder-Induced Bose-Einstein Condensate in a Quantum Spin Material at High Magnetic Fields

Abstract

The coupled spin-1 chains material NiCl2-4SC(NH2)2 (DTN) doped with Br impurities is expected to be a perfect candidate for observing many-body localization at high magnetic field: the so-called "Bose glass", a zero-temperature bosonic fluid, compressible, gapless, incoherent, and short-range correlated. Using nuclear magnetic resonance (NMR), we critically address the stability of the Bose glass in doped DTN, and find that it hosts a novel disorder-induced ordered state of matter, where many-body physics leads to an unexpected resurgence of quantum coherence emerging from localized impurity states. An experimental phase diagram of this new "order-from-disorder" phase, established from NMR T −1 1 relaxation rate data in the (13 ± 1)% Br-doped DTN, is found to be in excellent agreement with the theoretical prediction from large-scale quantum Monte Carlo simulations.

Simulating dirty bosons on a quantum computer

“…Furthermore, dirty boson physics play a role in chemically doped magnetic insulators [6,25] where disorder may lead to the localization of bosonic quasiparticles. Such spin compounds include the spin-1/2 coupled ladders (CH 3 ) 2 CHNH 3 Cu(Cl 0.95 Br 0.05 ) 3 [26], the S = 1/2 dimer system Tl 1−x K x CuCl 3 [27], the randomly diluted quantum spin-1/2 chains material (Yb 1−x Lu x ) 4 As 3 [28], and the S = 1 antiferromagnet Ni(Cl 1−x Br x ) 2 −4SC(NH 2 ) 2 at high magnetic fields [29][30][31][32][33][34].…”

Numerical study of the temperature dependence of the NMR relaxation rate across the superfluid–Bose glass transition in one dimension

“…It has also been observed in an array of quasi-one-dimensional samples of 39 K cold atoms, subject to a quasiperiodic optical lattice [14]. Another type of systems in which the Bose glass phase has been investigated are antiferromagnetic Mott insulators [15][16][17][18] such as the spin-1/2 ladder compound (CH 3 ) 2 CHNH 3 Cu(Cl x Br 1−x ) 3 [19] and the Br doped spin-1 system Ni(Cl 1−x Br x ) 2 -4SC(NH 2 ) 2 [20][21][22][23][24][25][26][27] to cite but a few [28,29].…”

Numerical study of the temperature dependence of the NMR relaxation rate across the superfluid-Bose glass transition in one dimension

“…It has also been observed in an array of quasi-one-dimensional samples of 39 K cold atoms, subject to a quasiperiodic optical lattice [14]. Another type of systems in which the Bose glass phase has been investigated are antiferromagnetic Mott insulators [15][16][17][18] such as the spin-1/2 ladder compound (CH 3 ) 2 CHNH 3 Cu(Cl x Br 1−x ) 3 [19] and the Br doped spin-1 system Ni(Cl 1−x Br x ) 2 -4SC(NH 2 ) 2 [20][21][22][23][24][25][26][27] to cite but a few [28,29].…”